When using catacomb do you drop your assistant at the catacomb or at the target tile after teleportation?
Following the sequence of events, you must leave or pick up an assistant to use a tile's action. Therefore you leave it at the Catacombs. You don't use the destination action. If you were to come back to the Catacombs again, the second time you could pick up the assistant you left the first time, then take the Catacombs action.