The party moves slowly past the first set of alcoves, and comes upon a second identical set some forty feet later. A sudden sound comes from behind, echoing eerily: the door has shut behind you, as if spring loaded. (No one detected the spring. FYI: I have you moving about 60' per round, if not a bit less, as I'm assuming you're making a rough map, or at least marking the way, as well as searching for traps/concealed doors and such).
The darkness looms ahead, past the lantern light. After the echo of the door dies, an uncomfortable silence settles.
ooc: actions?