Let’s move on.
To be honest, this plan seems a bit ridiculous, but I can’t imagine how else we could find out about Rayvelin’s disappearance and the vampire before we reach the island. Moreover, neither I nor Kael’drim even know about Rayvelin, so his absence in the cabin/wherever he might be on the ship won’t really tell us anything; that is, there was more of a calculation that after or during the “gathering,” someone would notice this. And now I also thought that it could only be Odd, who is on autopilot, Gordian, who is busy, and Thanasius.