[Tirinor]

I feel pretty strongly that if Frodo killed Sam he would then do himself in for shame. Of course, we are arguing the psychology of a fictional character, so maybe we should do ourselves in for shame. But seriously, Frodo's awareness of the ring, his love for Sam, the inherent quality that made him a "successful" ring bearer, the proximity of an immediate solution, all create an environment that would make frodo's post samicide suicide probable. But also seriously, Tolkien was a devout Catholic and I doubt that he would even consider having his hero commit suicide. so, eventhough I think from a psychological point of view Frodo's shakspearean tragic heroism is possible and perhaps probable, the probable literary reality is that suicide was very, very low on Tolkien's list of possible directions.

To answer the original question: What would I do? If Sam was me, I'd probably try to push Frodo in, going in with him if nessessary. If I was Sam, I would probably freak out and awkwardly wrestle and argue with frodo until he either snapped out of it or destroyed me.