I don't think it did explain the medical science. It was just McCoy at a workbench in the middle of sickbay. Any explanation would have been technobabble anyway. But it worked for me. McCoy was able to throw the super-regenerative switch somehow by using a sample of Khan's blood. An annoying fan's scoffing affected some of my experience, such as with Quinto screaming KHAAAAnnnnn...honestly the worst part of the last two films was the geek with a bug up their ass two seats to my left each time.....I thought the line was delivered all right though....there's no topping Shatner in this regard, but it was delivered well, and Spock vs. Khan was awesome.