The problem is they will never have enough good loaders. It is the toughest job in the building and the fact you do it well will be difficult to leave. There will always be a reason they need you to load.
As others have said, don’t intentionally slow down, work safer. Always leave an isle through the trucks until the end of the day. If you pull from cages, get a shepherds hook, don’t crawl into the cages to get packages from the back. Tape all open packages when you get them. Do everything the way your supposed to do it. And sign a bid sheet for driving to get out of the building.