Erel quickly switched to silent hand signals, gesturing for quiet, followed by pointing to the door, coupled with a hand gesture, estimating how many were inside. (If she cannot tell with her Perception check, she'll indicate four). She would very quietly test the door, to see if it is locked (23 Stealth), and, if not, gesture for the group to gather close, to spring the attack, as soon as she opened it. If it was, she'd gesture for them to stay back, then very quietly, attempt to unlock the door.