True. If she only said that enemies were invisible then he would probably trust her on that. Since you know - they have monsters that grow weapons from their back and she's nano-robot ghost or some shit. It was also kinda stupid that he was throwing a fit when literally everyone in the guild knew the first-timer rule. I'm pretty sure they would tell newcomers about it during registration process.
I hope that at least guy was smart enough to take few dozens of the regeneration pills. Stuff like this is worth more than gold on the post-apo wasteland like this one.