Sarissa has cast a LOT of buffing spells, most of which last 7-15 minutes (depending). How many minutes has it been since we entered this room? Are her minute-per-level buffs still going?
Assuming that they ARE still going, she prepares to open the west door. With a quick look at the others for confirmation, she says "Does anyone need a moment? If not, I'm opening this right now!"
She opens the door unless someone specifically says they need to wait.
If she is out of buffs, her action is different: "Give me just one moment." She recharges herself with Vigor. THEN she takes care of the door.