Legend said
Okay, this is how it works in the movies. When we track him down tomorrow, he ends up having some sort of super ace in the hole that we knew nothing about. We're promptly defeated, and more lives are lost before we can challenge him the second time and win.
This isn't the movies, though. Although I see your point. Maybe, I can get the location to Kelly, and she can become his "apprentice", so we can get any information of anything special he might have that we didn't know about. Although if he had anything like that, I'm rather completely sure I would have a counterpart, and thus I would know about it. But it's worth a try. This way, we ensure minimal death.