OwO <3

Seems only lightly destroyed

Well, its tracks are busted so it's stuck. Besides, a tank can look intact while still sustaining damage to the engine or interior. Just chuck a grenade down there and kaboom. Even an armor-piercing round can go in leaving a small hole but still doing massive internal damage, especially to the crew.

In this case, it appears as though one tread came off its track, and the other was blown off, given the way the fender is bent up. Secondly, the driver's hatch is open. It's possible he threw a grenade inside (or the crew got out and surrendered or ran away after the tracks were destroyed, as without those, the thing isn't going anywhere and is a sitting duck).