some answers
“userpy” is just the name given to the “user python” program, the VM does not know what the original name is.
sys.exit() does not stop the program, it throws an exception, that’s what is printing the red error popup and, because you are recursively calling functions, it would probably have many lines. Throwing an exception does not stop the motors so they will continue running with whatever the last command was.
The V5 brain does not run an OS in the conventional sense, so calls like sys.exit() will not work the same way as when running Python on a PC, I would avoid calls like that.
you should probably look at this topic, it will help when debugging Python programs.