diff --git a/Content.IntegrationTests/Tests/SaveLoadSaveTest.cs b/Content.IntegrationTests/Tests/SaveLoadSaveTest.cs
index 098be3cebd..7dfc2ffc1e 100644
--- a/Content.IntegrationTests/Tests/SaveLoadSaveTest.cs
+++ b/Content.IntegrationTests/Tests/SaveLoadSaveTest.cs
@@ -14,7 +14,7 @@ using Robust.Shared.Utility;
 namespace Content.IntegrationTests.Tests
 {
     /// <summary>
-    ///     Tests that a grid's yaml does not change when saved consecutively.
+    /// Tests that a grid's yaml does not change when saved consecutively.
     /// </summary>
     [TestFixture]
     public sealed partial class SaveLoadSaveTest : GameTest
@@ -28,26 +28,30 @@ namespace Content.IntegrationTests.Tests
             var mapLoader = entManager.System<MapLoaderSystem>();
             var mapSystem = entManager.System<SharedMapSystem>();
             var cfg = server.ResolveDependency<IConfigurationManager>();
-            Assert.That(cfg.GetCVar(CCVars.GridFill), Is.False);
+            Assume.That(cfg.GetCVar(CCVars.GridFill), Is.False);
 
             var testSystem = server.System<SaveLoadSaveTestSystem>();
             testSystem.Enabled = true;
 
+            Assume.That(SEntMan.EntityCount.Equals(0), "Lingering entities at the start of CreateSaveLoadSaveGrid");
+
             var rp1 = new ResPath("/save load save 1.yml");
             var rp2 = new ResPath("/save load save 2.yml");
 
+            MapId mapId0 = MapId.Nullspace;
+            MapId mapId1 = MapId.Nullspace;
+
             await server.WaitPost(() =>
             {
-                mapSystem.CreateMap(out var mapId0);
+                mapSystem.CreateMap(out mapId0);
                 var grid0 = mapSystem.CreateGridEntity(mapId0);
                 entManager.RunMapInit(grid0.Owner, entManager.GetComponent<MetaDataComponent>(grid0));
                 Assert.That(mapLoader.TrySaveGrid(grid0.Owner, rp1));
-                mapSystem.CreateMap(out var mapId1);
+                mapSystem.CreateMap(out mapId1);
                 Assert.That(mapLoader.TryLoadGrid(mapId1, rp1, out var grid1));
                 Assert.That(mapLoader.TrySaveGrid(grid1!.Value, rp2));
             });
 
-            await server.WaitIdleAsync();
             var userData = server.ResolveDependency<IResourceManager>().UserData;
 
             string one;
@@ -85,12 +89,18 @@ namespace Content.IntegrationTests.Tests
                 }
             });
             testSystem.Enabled = false;
+            await server.WaitPost(() =>
+            {
+                mapSystem.DeleteMap(mapId0);
+                mapSystem.DeleteMap(mapId1);
+            });
+            Assert.That(SEntMan.EntityCount.Equals(0), "Lingering entities at the end of CreateSaveLoadSaveGrid");
         }
 
         private new const string TestMap = "Maps/bagel.yml";
 
         /// <summary>
-        ///     Loads the default map, runs it for 5 ticks, then assert that it did not change.
+        /// Loads the default map, runs it for 5 ticks, then assert that it did not change.
         /// </summary>
         [Test]
         public async Task LoadSaveTicksSaveBagel()
@@ -102,6 +112,8 @@ namespace Content.IntegrationTests.Tests
             var testSystem = server.System<SaveLoadSaveTestSystem>();
             testSystem.Enabled = true;
 
+            Assume.That(SEntMan.EntityCount.Equals(0), "Lingering entities at the start of LoadSaveTicksSaveBagel");
+
             var rp1 = new ResPath("/load save ticks save 1.yml");
             var rp2 = new ResPath("/load save ticks save 2.yml");
 
@@ -110,23 +122,22 @@ namespace Content.IntegrationTests.Tests
             Assert.That(cfg.GetCVar(CCVars.GridFill), Is.False);
 
             // Load bagel.yml as uninitialized map, and save it to ensure it's up to date.
-            server.Post(() =>
+            await server.WaitPost(() =>
             {
                 var path = new ResPath(TestMap);
                 Assert.That(mapLoader.TryLoadMap(path, out var map, out _), $"Failed to load test map {TestMap}");
                 mapId = map!.Value.Comp.MapId;
                 Assert.That(mapLoader.TrySaveMap(mapId, rp1));
-            });
 
-            // Run 5 ticks.
-            server.RunTicks(5);
+                // Run 5 ticks.
+                server.RunTicks(5);
+            });
 
             await server.WaitPost(() =>
             {
                 Assert.That(mapLoader.TrySaveMap(mapId, rp2));
             });
 
-            await server.WaitIdleAsync();
             var userData = server.ResolveDependency<IResourceManager>().UserData;
 
             string one;
@@ -166,17 +177,18 @@ namespace Content.IntegrationTests.Tests
 
             testSystem.Enabled = false;
             await server.WaitPost(() => mapSys.DeleteMap(mapId));
+            Assert.That(SEntMan.EntityCount.Equals(0), "Lingering entities at the end of LoadSaveTicksSaveBagel");
         }
 
         /// <summary>
-        ///     Loads the same uninitialized map at slightly different times, and then checks that they are the same
-        ///     when getting saved.
+        /// Loads the same uninitialized map at slightly different times, and then checks that they are the same
+        /// when getting saved.
         /// </summary>
         /// <remarks>
-        ///     Should ensure that entities do not perform randomization prior to initialization and should prevents
-        ///     bugs like the one discussed in github.com/space-wizards/RobustToolbox/issues/3870. This test is somewhat
-        ///     similar to <see cref="LoadSaveTicksSaveBagel"/> and <see cref="SaveLoadSave"/>, but neither of these
-        ///     caught the mentioned bug.
+        /// Should ensure that entities do not perform randomization prior to initialization and should prevents
+        /// bugs like the one discussed in github.com/space-wizards/RobustToolbox/issues/3870. This test is somewhat
+        /// similar to <see cref="LoadSaveTicksSaveBagel"/> and <see cref="SaveLoadSave"/>, but neither of these
+        /// caught the mentioned bug.
         /// </remarks>
         [Test]
         public async Task LoadTickLoadBagel()
@@ -188,10 +200,12 @@ namespace Content.IntegrationTests.Tests
             var mapSys = server.System<SharedMapSystem>();
             var userData = server.ResolveDependency<IResourceManager>().UserData;
             var cfg = server.ResolveDependency<IConfigurationManager>();
-            Assert.That(cfg.GetCVar(CCVars.GridFill), Is.False);
+            Assume.That(cfg.GetCVar(CCVars.GridFill), Is.False);
             var testSystem = server.System<SaveLoadSaveTestSystem>();
             testSystem.Enabled = true;
 
+            Assume.That(SEntMan.EntityCount.Equals(0), "Lingering entities at the start of LoadTickLoadBagel");
+
             MapId mapId1 = default;
             MapId mapId2 = default;
             var fileA = new ResPath("/load tick load a.yml");
@@ -200,7 +214,7 @@ namespace Content.IntegrationTests.Tests
             string yamlB;
 
             // Load & save the first map
-            server.Post(() =>
+            await server.WaitPost(() =>
             {
                 var path = new ResPath(TestMap);
                 Assert.That(mapLoader.TryLoadMap(path, out var map, out _), $"Failed to load test map {TestMap}");
@@ -208,26 +222,23 @@ namespace Content.IntegrationTests.Tests
                 Assert.That(mapLoader.TrySaveMap(mapId1, fileA));
             });
 
-            await server.WaitIdleAsync();
             await using (var stream = userData.Open(fileA, FileMode.Open))
             using (var reader = new StreamReader(stream))
             {
                 yamlA = await reader.ReadToEndAsync();
             }
 
-            server.RunTicks(5);
-
             // Load & save the second map
-            server.Post(() =>
+            await server.WaitPost(() =>
             {
+                server.RunTicks(5);
+
                 var path = new ResPath(TestMap);
                 Assert.That(mapLoader.TryLoadMap(path, out var map, out _), $"Failed to load test map {TestMap}");
                 mapId2 = map!.Value.Comp.MapId;
                 Assert.That(mapLoader.TrySaveMap(mapId2, fileB));
             });
 
-            await server.WaitIdleAsync();
-
             await using (var stream = userData.Open(fileB, FileMode.Open))
             using (var reader = new StreamReader(stream))
             {
@@ -237,8 +248,12 @@ namespace Content.IntegrationTests.Tests
             Assert.That(yamlA, Is.EqualTo(yamlB));
 
             testSystem.Enabled = false;
-            await server.WaitPost(() => mapSys.DeleteMap(mapId1));
-            await server.WaitPost(() => mapSys.DeleteMap(mapId2));
+            await server.WaitPost(() =>
+            {
+                mapSys.DeleteMap(mapId1);
+                mapSys.DeleteMap(mapId2);
+            });
+            Assert.That(SEntMan.EntityCount.Equals(0), "Lingering entities at the end of LoadTickLoadBagel");
         }
 
         /// <summary>
diff --git a/Content.IntegrationTests/Tests/Stacks/StackTests.cs b/Content.IntegrationTests/Tests/Stacks/StackTests.cs
index 8dc07c8c88..7ae2f6fc1c 100644
--- a/Content.IntegrationTests/Tests/Stacks/StackTests.cs
+++ b/Content.IntegrationTests/Tests/Stacks/StackTests.cs
@@ -18,6 +18,8 @@ public sealed class StackTest : GameTest
     [Description("Tests for SharedStackSystem.SetCount.")]
     public async Task SetTest()
     {
+        Assume.That(SEntMan.EntityCount, Is.Zero, "Lingering entities at the start of the test.");
+
         var stack = await Spawn(StackEnt1);
 
         // Raising the count
@@ -33,7 +35,7 @@ public sealed class StackTest : GameTest
         Assert.That(_sStackSystem.GetCount(stack), Is.EqualTo(30));
 
         // Setting to 0 deletes the stack
-        await Server.WaitPost(() => _sStackSystem.SetCount((stack, null), 0));
+        Server.Post(() => _sStackSystem.SetCount((stack, null), 0));
         await Server.WaitRunTicks(1);
         Assert.That(SEntMan.EntityCount, Is.Zero);
     }
@@ -42,6 +44,8 @@ public sealed class StackTest : GameTest
     [Description("Tests that SharedStackSystem.MergeStacks functions as expected with small numbers.")]
     public async Task MergeTest()
     {
+        Assume.That(SEntMan.EntityCount, Is.Zero, "Lingering entities at the start of the test.");
+
         var stacks = new HashSet<EntityUid>();
 
         await Server.WaitPost(() =>
@@ -53,10 +57,10 @@ public sealed class StackTest : GameTest
             ];
 
             _sStackSystem.MergeStacks(ref stacks);
-        });
 
-        // Wait for the queue deletion of the empty stacks
-        await Server.WaitRunTicks(1);
+            // Need to wait for the queue deletion of the empty stacks
+            Server.RunTicks(1);
+        });
 
         using (Assert.EnterMultipleScope())
         {
@@ -74,6 +78,8 @@ public sealed class StackTest : GameTest
     [Description("Tests that SharedStackSystem.MergeStacks functions as expected with large numbers.")]
     public async Task MergeOverflowTest()
     {
+        Assume.That(SEntMan.EntityCount, Is.Zero, "Lingering entities at the start of the test.");
+
         var stacks = new HashSet<EntityUid>();
 
         await Server.WaitPost(() =>
@@ -86,10 +92,10 @@ public sealed class StackTest : GameTest
             ];
 
             _sStackSystem.MergeStacks(ref stacks);
-        });
 
-        // Wait for the queue deletion of the empty stacks
-        await Server.WaitRunTicks(1);
+            // Wait for the queue deletion of the empty stacks
+            Server.RunTicks(1);
+        });
 
         var count = 0;
         await Server.WaitPost(() =>
@@ -113,20 +119,25 @@ public sealed class StackTest : GameTest
     }
 
     [Test]
-    [Description("Test for SharedStackSystem.TryMergeToContacts .")]
+    [Description("Test for SharedStackSystem.TryMergeToContacts.")]
     public async Task MergeContactsTest()
     {
         var map = await Pair.CreateTestMap();
-        await Server.WaitIdleAsync();
 
         // Spawn two stacks at the same position so they're contacting
-        var donor = await SpawnAtPosition(StackEnt1, map.GridCoords);
-        var receiver = await SpawnAtPosition(StackEnt1, map.GridCoords);
+        EntityUid donor = EntityUid.Invalid;
+        EntityUid receiver = EntityUid.Invalid;
 
-        await Server.WaitPost(() => _sStackSystem.TryMergeToContacts(donor));
+        await Server.WaitPost(() =>
+        {
+            donor = SSpawnAtPosition(StackEnt1, map.GridCoords);
+            receiver = SSpawnAtPosition(StackEnt1, map.GridCoords);
 
-        // Wait for queue deletion
-        await Server.WaitRunTicks(1);
+            _sStackSystem.TryMergeToContacts(donor);
+
+            // Wait for queue deletion
+            Server.RunTicks(1);
+        });
 
         using (Assert.EnterMultipleScope())
         {
@@ -137,9 +148,11 @@ public sealed class StackTest : GameTest
         }
 
         // Now test for when there's more count than the receiver can hold
-        donor = await SpawnAtPosition(StackEnt30, map.GridCoords);
-
-        await Server.WaitPost(() => _sStackSystem.TryMergeToContacts(donor));
+        await Server.WaitPost(() =>
+        {
+            donor = SSpawnAtPosition(StackEnt30, map.GridCoords);
+            _sStackSystem.TryMergeToContacts(donor);
+        });
 
         using (Assert.EnterMultipleScope())
         {