It concerns ep 102 (I think I have the number right) where Katse is unmasked. There is a decision made by Ken to allow Katse to escape, rather than kill the enemy. (I know Sosai was involved too, but ultimately, Ken let Katse escape) It's a tough decision to be sure but one that maybe he later regrets seeing as Joe is left behind in the Himalayas.
Now, I'm going to flip this on its head (and thus why I put it in the BotP thread). Do you think Mark would have done the same for Zoltar? Of course we don't see this ep in BotP but it was a thought that occurred to me as I was falling asleep.
Now, we not only have 2 separate teams but differing dynamics as well. So it boils down to this: would the BotP crew do the same as the Gatch team if put into the same situation? Of course, neither has a crystal ball to know the ultimate outcome of this decision and that's the conclusion of ep 105.
I'll start out by saying the BotP crew wouldn't leave Jason behind in 105 - they would have found a way to get him back to the ship one way of another.

But getting back to Mark. I think he would make the same decision as Ken. Mark can be cold-blooded but I don't believe he's that heartless. I also think if he did kill Zoltar, he might have a mutiny on his hands as his team would no longer follow him, including Jason who was the most in danger in ep 102.