That's actually one of my favorite things in Knights of the Morningstar and I really like that Rawn brought out this point. I would argue that not only is Sam's desire to return home unselfish, but there's an aspect to his choosing to keep leaping that is actually extremely selfish, even while it's also selfless at the same time. In the Sam Beckett character thread wakkanne made the excellent point that Sam got so involved with school and his work that he didn't go home when the family lost the farm, or when his father died, or when Katie was in an abusive marriage. Those were times when his family needed him and he wasn't there. And here he is, how many years later, leaping and even talking to Al about how much he regrets not being there those times, and still making the same mistake now of not being there in the present for his family and friends.
I love this, especially that last sentence, and thank you for quoting me. Without giving anything away, the entire subplot of my novella, Love's Young Dream, deals with this issue.
Speaking of which Mirror's Edge brilliantly uses Tom in the present day to express how even when Sam was around his family he still actually wasn't as he was up in his head working on his theories. Something Donna admitted to noticing as well (there is even a flashback where she's straight up asks him for sex while he's working late but he denies her) but knew what she married into and expressed more than once that she could never want another. Her love for him was unbreakable.
Haha! I must have been subconsciously (or maybe consciously 20 years ago) referencing the "Mirror's Edge" novel in my writing. I had totally forgotten about that, but it rings true in my book, Love's Young Dream, which I began 20 years ago and just finished last year.