["Perhaps you would like to do something more productive with your time? Surely you didn't claw your way out of whatever hellhole you came from and left all those people behind to follow me around like a yapping dog too cowardly to bite?"
...He doesn't say that out loud. While still walking, back turned to Porthos:]
Please let me know if you spot any. That way we will be done here faster. [No, Sebastian needs no help looking. He might as well have said "look how seriously I'm taking your threat".]