I was under the idea that the cell doors open outwards to avoid that exact situation. Though, I'm sure that is not a universal truth. I also think I read that his cell was under constant closed circuit video surveillance. I'm not saying he didn't commit suicide, but there's some questionable circumstances if he did, and the guards on duty should probably have to answer some hard questions.
And, to be clear, I find it a shame that he did take the easy way out by committing suicide. He deserved to suffer more punishment for the crime he was found guilty of. Not to mention other crimes he may also have committed.