I already posted this at Messerforum.net and I think I should share it with you guys, too!
Yesterday I heard a loud noise from my brother's room, as if something fell to the ground (hard to describe). I was curious, went to him and saw that his 6V Wolf-Eyes with LED-tailcap had exploded. Only the tailcap was damaged. I think he's lucky that he didn't use his other tailcap which is more rugged and wouldn't have let the pressure out that easily. So noone was injured, but the tailcap is toast.
Just for the record: The batteries were not dead, but low enough that the xenon bulb wouldn't work. The batteries were still good enough for the LEDs in the tailcap, that's why he left the batteries in the flashlight. He never changed their position and they were both new when he put them in.
I think I should get him a Fenix now. It's my fault that he got this pipe-bomb in the first place. Be careful with lithiums!