I'm basing my response on pictures of such things that I've seen over the years. I've never been in a tank or seen one explode in person (and I'm happy about the latter). You can find a few pictures by doing a
Google image search for "Exploded WWII Tank" (without the quotation marks). (You'll also get a couple interesting diagrams of WWII tanks.)
The only certainty is that there'll be a tremendous fire. The turret may or may not come off. If it does come off, it's likely to just fall off one side or the other. Popping up 30 feet in the air and landing 30 feet away is cinematic.
Unless shrapnel from the explosion hits the PC, the PC should be able to move away quickly enough to avoid damage. Moving may expose the PC to attacks from the enemy, but very few people would stick around to get cooked.