CordwainerFish
Cosmic Mongoose
Not freeze or boil, but rather appear inside the destination ship still keeping the relative velocity of the origination ship. Say hello to Mr. Bulkhead at however many meters per second.So, if I understand correctly : if a psion wants to teleport from 1 ship to another, the psion's ship must match vector with the target ship (otherwise, the psion might boil or freeze himself to death)...
I don't know how easy it is these days to get a hold of Larry Niven's essay "The Theory and Practice of Teleportation", but I'd bet long that it and/or Niven's fiction inspired Trav's rules.