If ull run the event code more then one time, lets say twice at once, iam pretty sure this leads to that shaking. Deactivate the event directly after it was called, and reactivate it, if lift - movement is done. Besides that, if u dont use "levercrater" somewhere else i would use "my" as pointer in the whiles. Btw. i wont put whiles in events.
Please note: if the lift moves u should check below and above ( via c_trace + use_box ) that the lift is able to reach its end, say a model walks below the lift ( and keeps standing ) ull have a never ending while.
edit: If you have a function / void handling the camera, maybe
fixes the prob ( a wild guess ).
Greets