Costigan sighs. He straightens, in an unconscious gesture of defiance, crossing his arms. Evandau's question sounds like a clarification. The undercover hears it as an accusation, one he has to fight again. Of course, there's a part of him that knows it's because he feels guilty for it, that Evandau's question mirrors his own doubts back at him.

Then his arms fall away and return to his pockets instead, the momentary desire for conflict passing. He shrugs his jacket open in a vague motion of metaphorical surrender, his anxiety no longer threatening to overwhelm and yet remaining his constant companion. "I don't see a better option. Do you?"