::The narrative purpose of the Sentry was to have the Marvel Universe's most powerful character also a character with terrible mental illness, his only weakness, his own worst enemy. You can only really appreciate him if you suspend whatever disbelief it takes to accept that, okay, fuck Galactus, fuck Terrax, and definitely fuck the Hulk, because the Sentry is (was) #1. Because they said so, that's all. He was called "omnipotent" and "immortal", and I'm sure we've not seen the last of him. (Haters, just stifle yourselves, willya?) 
 ::There's no reason to believe Sentry was truly motivated to take down the WWH Hulk. He may have been bashing him with all his might, but that's not the same as wanting him dead. He punched the Hulk around when he could have simply stopped his heart, or torn his skull open and eaten his brain. It was a boisterous fight between friends; despite the flaming destruction, no one was trying to kill anyone. If Reynolds had released the Void, it would have been a vastly different, much sadder story, because the Hulk would be dead forever. 
 ::The Sentry and the Void are far, FAR stronger than the Hulk. But Hulk is more emotionally together  and that's saying something! 
 ::