Emotionally, I think it is a good scene. But it really doesn't make any sense. Why would Khan have to come down to Regula to kill them? Why couldn't he beam the survivors up just like he beamed up the Genesis Device?
I think because sensors can't see that far down into the rock. That's why on Regula I they couldn't see where they had beamed down. They needed coordinates. Khan couldn't just fire away the transporters, hoping to pick someone up.
I also think Kirk's scream is genuine. He has a plan, but he's still pissed at Khan.