Unexplainable Freezing

This almost seems hopeless but I'll try to explain
I'm making a ladder map where there are waves of enemies. Everything works fine except randomly the map will freeze with no error message and I have to end program using the task manager.

It doesn't happen when a trigger is activated (and I'm sure of this) because it happens at different times during different waves. However it does only happen when there are enemies present. It also only started happening recently,

I have tried everything including playing the map on another computer and deleting loads of triggers.

The only thing I can think of is that it may have to do with Info_nodes. I placed them kinda sloppily but I cant see why this would make a problem.

Any help would be great in this unexplainable freezing.

I figured it out. It had to do with a double door trigger. Each door had an output to open the other door and when the NPC's opened the door it crashed. It took about 35 runthroughs to find that. But it works!