That-- is unexpected, although the part that takes him off-guard is not 'it's Bruce' so much as perhaps the last sense-memory he expected to have triggered here, of all places. Under his breath, “Don't tell me you broke your ribs again.”

(No, that's probably not what he means.)

His voice sounds off, even as quiet as he speaks; the mask is fixed in place and has little give, muffling him, making it harder to move his jaw, and though there's relief and grim humour in the words, there's pain that he's been gritting his teeth through since this began. He holds himself steady all the same - alert, keyed up in a way he'll crash from later (hard), listening and waiting and spoiling for a fight.