diff --git a/1.4/Assemblies/PerformanceFish.dll b/1.4/Assemblies/PerformanceFish.dll
index 7577b4a..ae4dc30 100644
Binary files a/1.4/Assemblies/PerformanceFish.dll and b/1.4/Assemblies/PerformanceFish.dll differ
diff --git a/1.4/Assemblies/PerformanceFish.pdb b/1.4/Assemblies/PerformanceFish.pdb
index ebdbbe0..03d1be7 100644
Binary files a/1.4/Assemblies/PerformanceFish.pdb and b/1.4/Assemblies/PerformanceFish.pdb differ
diff --git a/Source/PerformanceFish/Listers/ThingOwnerOptimization.cs b/Source/PerformanceFish/Listers/ThingOwnerOptimization.cs
index f920952..815462a 100644
--- a/Source/PerformanceFish/Listers/ThingOwnerOptimization.cs
+++ b/Source/PerformanceFish/Listers/ThingOwnerOptimization.cs
@@ -137,7 +137,7 @@ public sealed class ThingOwnerOptimization : ClassWithFishPrepatches
 					: innerList.LastIndexOf((T)item);
 			
 			if (index >= 0)
-				innerList.RemoveAtFastUnordered(index);
+				innerList.RemoveAtFastUnorderedUnsafe(index);
 			
 			indexMap.Remove(itemKey);
 			
diff --git a/Source/PerformanceFish/PerformanceFish.csproj b/Source/PerformanceFish/PerformanceFish.csproj
index e136c69..f564521 100644
--- a/Source/PerformanceFish/PerformanceFish.csproj
+++ b/Source/PerformanceFish/PerformanceFish.csproj
@@ -17,7 +17,7 @@
 		<Nullable>enable</Nullable>
 		<AllowUnsafeBlocks>True</AllowUnsafeBlocks>
 		<Configurations>v1.4</Configurations>
-		<Version>0.3.999.9</Version>
+		<Version>0.3.999.91</Version>
 		<NoWarn>
 			1701;1702;IL2121;CS8500;CS9082;CA1000;CA1002;CA1003;CA1707;CA1010;CA1715;CA1716;CA1724;CA1031;CA1033;
 			CA1034;CA1043;CA1051;CA1305;CA1310;CA1710;CA1711;CA1810;CA1812;CA1819;CA1851;CA2002;CA5394;CA1725;CA1062
diff --git a/Source/PerformanceFish/Utility/CollectionExtensions.cs b/Source/PerformanceFish/Utility/CollectionExtensions.cs
index 482ce82..1ae2706 100644
--- a/Source/PerformanceFish/Utility/CollectionExtensions.cs
+++ b/Source/PerformanceFish/Utility/CollectionExtensions.cs
@@ -5,7 +5,6 @@
 
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
-using Mono.Collections.Generic;
 
 namespace PerformanceFish.Utility;
 
@@ -296,6 +295,17 @@ public static class CollectionExtensions
 
 		return ThrowForNoElements<T>();
 	}
+	
+	public static unsafe void RemoveAtFastUnorderedUnsafe<T>(this List<T> list, int index)
+	{
+		fixed (T* lastBucket = &list._items[list._size - 1])
+		{
+			list[index] = *lastBucket;
+			*lastBucket = default;
+		}
+
+		list._size--;
+	}
 
 	public static List<T> AsOrToList<T>(this IEnumerable<T> enumerable) => enumerable as List<T> ?? enumerable.ToList();