From my experience with burnt out Pact style vehicles, all of them were burnt out. Even the small penetrators when they send the penetrator rods through they send molten metal inside the compartment which starts things afire as well.
And we have the rear hatch fuel tank as I have mentioned which catches fire easily enough again setting them afire.
The ones I see that would survive enough to be rebuilt,
mobility kills, the engine, transmission or drive train is damaged the vehicle is abandoned. <provided the engine doesn't burn> This however is a simple modular repair but, the parts to a non standard vehicle may be a problem.
Mine, rocket launcher or light ordinance hit to the drive train, again taking out a couple wheels.
Bogged down in a tank trap or swamp or soft soil or even a river crossing.
A concussion that kills the crew.
A vehicle accident, a roll over, or even the vehicle slides from a slope, or down a hill etc and the crew is injured or killed.
The crew is shot while out of the vehicle.
Those are just some of the ideas I can see where a Pact vehicle would be taken intact.
However, one question, often vehicles that are forced to be abandoned or about to be surrendered are usualy destroyed, it is quite common among most forces to destroy or disable equipment that has to be abandoned so it can not be of use to the enemy.