So all this time glasses girl could've snitched on big guy's mask ability and yet didn't do it?
"I have to use violence to kidnap Yuiichi", actually he was injured and probably asleep. You could've gently tied him up and gently carry him (which probably doesn't count as violence) outside to assault him. Also I hate how at any point in time no one brought up the fact that individual tasks have a time limit, so stalling could be a good idea to expose perpetrators.
Ok 2 options, leave the cabin for 10mins until the time is up to escape the poop OR untie someone who is probably the perpetrator. Or even many other options I don't get why they untied him