[ It's the not knowing that kills him. Like something just whisks them away as quickly as they came. Too many things could have happened. ]

Kaneki isn't the first who left something behind. That's how I found out Eleven disappeared. [ He somehow knows that he gave him that money as a parting gift. Which means he had enough time to think about it. ]

They might not be related, but this isn't the only time we've been somewhere dangerous. There has to be some way to find out where they went.