Flint's reaction yields the tiniest of smirks from Barrow, in a sort of commiserating way rather than anything actually being funny.
He's mid-drink when Granitefell is invoked, and although his recovery is quick, there's a little cough that emanates from behind the tankard, which is swiftly pulled away, and Barrow's resulting posture is tense.

"Bad luck," he repeats hoarsely, still clearing the ale from his windpipe.