They don't have to wait much - Rewind and Silica were close enough to the PHQ that: 1. the other heroes arrive pretty quickly and 2. they suspect this may be a trap. They arrive en masse: Glam (plus three copies), Lorica, Drupe, Dauntless, Miss Militia, Velocity, and Glimmer. Glam provides everyone with imaginary air filters because of Fog, and the heroes who had exposed skin also covered it for the same reason.

They get on a roof a couple of blocks away.