I don’t think he’s particularly mad about being called nurse. Rather, the hurt came from something much deeper. (incoming rant)
Think about it. When his team disbanded, Medic went to pursue his passion: medicine. He did so by joining TFC, in order to gain access to black market animal organs and funding for his experiments. He even experimented on the TFC guys just to satisfy his curiosity. He doesn’t care what team he’s on, as long as he can do experiments. Which is why we see him being ‘evil’ despite him not siding with anyone, when in reality he’s just aloof. For Medic, teams/comrades/ethics come second, medicine comes first.
But then we have this scene, TFC Heavy barging in and saw that Medic’s bringing Sniper back to life. He got mad and says things like these.
Medic brought Sniper back to life after he’s been dead for 6 hours. It’s certainly a breakthrough in modern medicine. Medic is good at it and he knows it, he calls himself God many times, for accomplishing things that are impossible.
But TFC Heavy doesn’t see that. He thinks Medic is useless, always causing trouble for him because Medic didn’t follow his orders. Furthermore, TFC Heavy always berate Medic, calling him with racist slurs and never acknowledge his achievements. He also doesn’t appreciate Medic healing him, when he swatted the Medigun off.
How long has Medic endured such treatment? 6 months? Despite being detached from human feelings, it even wears him down. I think it speaks volumes that Medic feels happy when he sees Sniper, his old teammate.
And even though his old teammates attitudes towards him aren’t special, they didn’t berate him like that. They didn’t try to control him, and heck they need him for uber and heals deep down they respect Medic for that.. (They even got better - take for example Soldier especially, he isn’t racist anymore especially after he went to Heavy’s.)
I think it’s a big deal when the most uncaring person in the team take insult from TFC Heavy’s nasty treatment. Him swatting away the medigun is probably what broke the camel’s back.
Lastly, look at Medic’s face in the last panel. Do you recognise it?
It’s the face of someone who’s gonna practice medicine.