The point of "escape or die" situations is to avoid that kind of thing. That way our heroic image is preserved (we aren't even indirectly responsible for van Baelsar's death) but the villain is still vanquished, never to menace the world again.
Would you really argue that Henry Ducard / Ra's al Ghul could have survived at the end of Batman Begins? After the out-of-control train he was riding on crashed into a building? It's a very similar scenario.
Or could it just be that people are grasping at straws and trying to find some way Gaius could be not dead because he was a popular villain? I like him as a villain, but when we were stuck in an escape or die situation so was he; we escaped, he did not. Gotta learn when to let go...
Again, as long as people are admitting it's just wishful thinking...
... but there's not really any evidence to support Gaius still living except the fact we do not have his head on a pike. We shouldn't need it, for kupo's sake.
And as always, I apologize if I'm being a bit acerbic. That's just how I am.