I was thinking of just filling in where needed, so I don't necessarily want the copilot job if Aether wants it. As he pointed out, it's perfectly reasonable for people to have more than one skill, so I would be fine with my medical guy (McPherson) coming on as a gun-toter. Never hurts to have someone else with some emergency medical experience, and could be interesting depending on the other medic's background and level of training. (some in-character "I believe I know more about this than you" situations, perhaps)
My idea for this character was that he's just left everything behind and looking for a place to settle, so he stays on the ship with no specific destination or time frame in mind, and from there can get caught up in the events of the day.
So, let me know if you're interested.