It's an exploit to use the Pak crew for scouting/combat. And in the event the crew doesn't retreat you can move it to your spawn(or any friendly spawn) and hit the toggle retreat the same way you would for a tank. I've retreated a few crews for anything by hitting crew retreat by mistake instead of what i wanted. it happens. it's annoying, but you deal with it
I believe the Toggle retreat button and all other retreat buttons are missing on the crew.