I think what you might actually want is a fusable link. They tend to be used for high amperage like that

First off how dead is the battery? Even a 5km drive should be enough to restart a warm engine if the battery was just discharged and doesn’t have any actual problems.

Secondly while it won’t hurt the car they probably won’t authorize the pumps to start if the car is still running as it is illigal with gas. Technically it’s also illegal with diesel but it’s kind of standard operating practice with fleets because diesel is very difficult to accidentally ignite.