I think his growth came from him being too cowardly to go on the mission at all because he didn’t want to die, to willingly giving up his life (so he thought) to save Rocky. That’s cool I guess, but it would have been pretty awesome for the Eridians to build him a one-way ship as soon as he got there so he could go back to Earth and meet up with everyone he’d once known. His coworkers would all be old or maybe even passed away. The kids he was so invested in that he couldn’t even cuss would be adults now (the ones who lived anyway). Let’s have him meet that smart asshole student and see what became of her! But nope. Instead we’ll just fuck off to Erid forever. Good luck Earth, nice knowing you!