When Lo Pan got destroyed. Thunder, one of the 3 Storms who was fighting Wang, got destroyed as a result. At least that’s why I think he died. He inflated to the point of blowing up.
If that’s the case then why didn’t anything happen to the other one who arrived soon after? Think it was Lightning or Rain. That’s a question that’s been in my mind for sometime now because it didn’t make sense to me at the time.
I don't think Thunder died because they'd killed Lo Pan. He blew himself up out of rage, only after seeing Lo Pan's body.
We already know from the earlier escape sequence that Thunder can inflate himself.
Unlike cool-headed Rain, Thunder is a hot-head and loses control - that's why he was demolishing furniture unnecessarily while trying to catch Wang.
So when he saw his dead master, he just lost it. He inflated until he popped.
The entire movie is comical/satirical, and this scene should be taken in that light. It was an irrational move from an irrational character.
Funny, too, that he was the most vocal of the storms, considering he spoke the least English. James Pax (Lightning) is a graduate of NYU and USC, and Peter Kwong (Rain) is an American (of Chinese descent - but language isn't genetic)