That is, if Ricard remembers correctly that this guy slept in their room
Just by process of elimination I came by the name of Sam Sandler, since it can't be Ricard, the Korean guy (Lee Ilgyu) or Paul vd Wolf, since those are accounted for. Sam Sandler is the only one left that slept in that room, according to the PDF that was sent to us by René and the rest of the organisation.