Even though he was supposed to be in his stealth mode at the moment, and the puppets shouldn't be able to 'see' him, he was still careful not to fall into a trap.
After all, he had already used a Medium Stealth Talisman and those SP points, it would be quite a shame if he had to waste more points, and treasures to deal with this situation.
With those thoughts in his mind, he proceeded forwards slowly and carefully but even after walking for 49 meters, there was no sign of those puppets inside the tunnel.
It was only when he finally passed the 50-meter mark that he suddenly felt that change in energy once again, and that his instincts finally started acting up again.
He wasn't stupid to not understand that this 50 meters mark functioned as some kind of switch for those puppets, and now that he had turned it on his whereabouts were discovered.