Seth returns the smile, though it's equally fleeting and small, if not more so. He wants to comment on how archaeologist isn't really the most impressive word Daniel could've chosen to describe himself, but he's not really feeling the playful banter right now.

"I know..." he answers, sinking a little in his seat, his shoulders hunching. "I just... I don't want that to be the only thing standing between me and..."

He lets the sentence end there, as they both know what he means. Daniel's already seen what kind of hopelessness the thought of imprisonment fills Seth with, and what lengths he'd go to to avoid it. He knows he's not being entirely rational about this, but he has good reasons for it.