Same thing that happens if your ICE vehicle quits. Call a roll-back and haul it to the charger.
Did that once with my Dodge 3/4 ton Cummins when the fan belt pulley came off and de-railed the serpentine belt. I didn't haul it to a charger, but instead to my shop, where I repaired it. 45 miles hauling charge on that one.
Edit to add:
On hauling a charger to charge battery. Takes a big charger to charge in a reasonable time. A 5 KW charger might add 10 to 15 miles of range for every hour charging. That's if everything is right. If you were stupid and absolutely ignored all warnings, then you might end up killing the control battery and might need to replace that, in addition to charging the traction battery. Not a whole lot of difference from running a diesel until it dies from lack of fuel and then grinding the starter until you wreck things there too.