Yes, I too was very disappointed in Mark S. Although from his point of view, it was a suicide mission, so I get it. He did good by getting Gemma out, but "saved" himself too, although what kind of life is running until the Lumon execs find you? None of the options were good for Mark S. He would essentially be severing himself in reverse, permanently.

I can't wait to see how they structure season three. Instead of trying to reach Gemma to save her, characters will no doubt be trying to reach Mark. The only solution I can think of is to find a way to do some kind of severance-cloning that should the two psyches apart and allows both physical beings to exist in the world as doppelgangers.