Ian,
In the rules as originally written you would have to leave 2 men from the squad in the vehicle, one to act as driver the other to man the MG. It would become an Uncommanded Vehicle and only one crew position could be activated each phase using a Command Dice of ¡®1¡¯ limiting its ability to function effectively as a fighting vehicle. In some later lists German half tracks come with a driver and gunner so the whole squad can dismount but it would still count as an uncommanded vehicle once the JL had moved away.
John