diff --git a/src/main/java/de/ph87/electro/circuit/Circuit.java b/src/main/java/de/ph87/electro/circuit/Circuit.java
index 26bf27c..b96c2eb 100644
--- a/src/main/java/de/ph87/electro/circuit/Circuit.java
+++ b/src/main/java/de/ph87/electro/circuit/Circuit.java
@@ -80,7 +80,7 @@ public class Circuit {
 
   public void removePart(final Part part) {
     if (parts.remove(part)) {
-      part.getJunctions().forEach(junction -> junction.getWires().forEach(this::disconnect));
+      part.getJunctions().stream().flatMap(junction -> junction.getWires().stream()).toList().forEach(this::disconnect); // jep, first toList(), then forEach (due to concurrent modification)
     } else {
       throw new RuntimeException();
     }