Dana Shilling wrote:
well, WHENEVER you have the chance to kill an implacable enemy who has been driven insane by a desire for vengeance on you... kill him!
Except that part of Blake's point here -- and I think it's the real reason why he doesn't kill Travis at other opportunities, as well -- seems to be "better the devil you know." He doesn't want to kill Travis because he knows, no matter what, *someone* is going to be after him, and he wants it to be Travis because he knows how Travis thinks, which gives him an advantage when it comes to *out*thinking him. Kill Travis, somebody new takes his place, and Blake loses that advantage. Ultimately, this *may* have been a mistake on Blake's part, but it's far from irrational.