I'd add that I understand why they needed to raise the possibility that Clark killed Knox -- so Lex could drop the revelation to Clark that Knox is actually immortal. I just think there are ways they could have done it without either (a) raising the possibility that not only is it potentially deadly when Clark does the 30 Foot Toss, but that Clark is aware the 30 Foot Toss could be deadly, or (2) making it seem like Clark doesn't recognize that he chose how to neutralize Knox and that that means the consequences of that choice are his alone to bear. Clark had plenty of other legitimate reasons to morally lambaste Lex during that scene, his 33.1 experiments chief among them. He didn't need to be all "Wah, I killed someone because of you!" to have the moral high ground there, particularly not when he actually did have control over what he did with Knox. Just punching the guy would have been enough to put him down, you know? It's not on Lex if Clark's default fight maneuver is Hurl Someone Into the Next County Over.