River's head snaps over towards Duo; she's at his heels before the look of confusion has quite faded.

(River has a disadvantage here of not always being sure what she's really hearing, not to mention not being familiar with Preventers SOP. It might have taken her a minute to put together that cheery complex-wide announcement with the fact that they're trying for secrecy.)

Through the door -- they both scuttle through low, this time -- and onto the balcony. Below, the room is suddenly a whole lot busier.