Kerith would have been happy to stop right there, for the time being. The door was one thing, but this was another door, which might actually lead to a room with yeti.
But as the 'encouragement' mounted, first Oren, then Alexi; Kerith, with a questioning look back at the others, says, "Somebody see if they can hold that other door open with a rock or something. I want to keep our avenue of retreat open."
Once that's seen to, Kerith will pull the second latch open.