The only gallery CG that's not on his route is the first one. You get that by playing a different route at this point in time.
I already gotten the one with him watching the move, driving the car, picking Dave up when he's punched, but what else? Do you mind giving me hints? I really want to find out, answers or hints will do good. Watch this, because it is what I need. https://wiki.teamfortress.com/w/images/d/da/Medic_helpme02.wav