He's trying so hard, jaw set as he resists the call of the demon. The last couple of days shook him to his core and although he'll be back to his usual snarky self before long, that cocky facade is mostly dropped until they've gotten this whole mess settled. That also means no snide remarks, no taunting, no nothing.
And then Jack throws that offer out on the table and he can't help but groan. Fuck you, Jack Harkness.
"Are you serious?"
His eyes narrow, still yellow and feral. Don't be cruel. He's been living off bottled blood for months and it's gross as hell in comparison. This is like waving a kobe beef in front of someone who's lived off White Castle burgers and nothing but.