diff --git a/overlay/oxide/plugins/RunicGatewayZones.cs b/overlay/oxide/plugins/RunicGatewayZones.cs
index de90edd..33c2ecb 100644
--- a/overlay/oxide/plugins/RunicGatewayZones.cs
+++ b/overlay/oxide/plugins/RunicGatewayZones.cs
@@ -292,7 +292,9 @@ namespace Oxide.Plugins
 
             int entered = 0;
 
-            foreach (BasePlayer player in BasePlayer.activePlayerList.ToArray())
+            // A copy: entering a player can eject or kill them, which changes the live list.
+            // `activePlayerList` is Facepunch's ListHashSet, which has no ToArray.
+            foreach (BasePlayer player in new List<BasePlayer>(BasePlayer.activePlayerList))
             {
                 if (player == null || player.IsNpc || player.transform == null)
                     continue;