I gave it a try but sadly it's pretty unpredictable.

Most of the time it results in a script crash. If that happens, sometimes the engine exits correctly (log ends with "Close window at ..."), other times it crashes right after the error (the last line in the log in that case only says "Error E1513: Script crash in ...: " and that's it)

When the level_load() crashed I think there also was a "bad file format" error. I guess something writes to memory that it shouldn't write to, overwriting parts of the the file's content while loading, in that case.

We're currently trying to make sure that no functions which use entities or other level content are running before loading a new map. It's a bit tricky though, since it looks like the engine automatically terminates actions that are set on ent_create().