The event handler has nothing to do with the crash and can be omitted to reproduce it - FYI.
I fixed the previous problem and thought I tested it but forgot that Multiplayer -> new game doesn't *actually* run the multiplayer code but instead is just single player with MP support once someone connects so I missed the 2nd part of the problem.
Anyway, the crash is fixed for 0.15.5 and is actually tested in MP now after setting up a dedicated server to confirm
If you want to get ahold of me I'm almost always on Discord.