Conveyor Belt part in a model makes entire model into one

I’m trying to make a good conveyor belt for a map, however, all the tutorials I’ve seen have the same sort of method. Setting the velocity of the script’s parent. However, as the conveyor belt is welded, the velocity is applied to the entire model.

What I want to happen:
Player steps on conveyor belt, moves in one direction.

What happens:

Why is the conveyor belt welded?

its a part of a destructible map