The crew abandons the vehicle (D5.341). And the crew is forbidden to re-enter the vehicle afterwards.
It was to some temporary annoyance that I learned about this little rules gem in my just completed Dinant CG...
"
D5.341... A bogged/immobilized Recalled AFV must be Abandoned instead; its crew is no longer obliged to leave the board, but may not re-crew
that AFV."
The prohibition to reenter a vehicle seems to be limited to the exact one which had to be Abandoned while under Recall.
So the Crew could enter another Abandoned vehicle I believe.
Under normal circumstances, this situation will rarely arise. But in a Campaign Game such as Dinant, an opportunity to take advantage of this might indeed present itself.
von Marwitz