I didn't expect that guy to be a police officer. Still, Oto and Akiba are far too naive and careless. Akiba kept his hobby a secret for a long time, so such carelessness is probably due to things progressing too fast for him now. He's not the one initiating all of these outgoing changes, so he hasn't had the time to figure out how to do it safely and get mentally prepared for all the dangers and challenges. That being said, I still blame the studio for not having locks in the doors. Even if it's Japan, that's still crazy.