Imagine the stark contrast of Mark's work ethic after the paradox was resolved.
Like, man spent multiple lifetimes isolated, feeling betrayed, working on tech thousands of years ahead of his people's current capabilities. Switching to work on colony shuttles must be jarringly easily in comparison. And his social skills must be SHIT.
The rest of the crew don't know what he went through except for maybe some vague memories of multiple timelines. Then they arrive at their new home, and suddenly Mark is THE MOST efficient worker they've ever seen in their godamn lives. He gets his hands on a engine and goes dead silent from start to finish, he's lost the charm he used to have talking to the crew, its almost scary watching him work.
Imagine what Celci would think of this guy who used to insist on putting glass windows on a spaceship to this now,, quiet, somber engineer who works on machines like its the only thing he remembers how to do.