Sharpie?
Why can't an innie write a very important message (tm) on the stairwell window with a sharpie, then run out and their confused outie will turn around and see it on the door window? It will work only once with the alarms going off when the door opens, but if you are fast and the security guy is distracted, you can deliver it? like "Run!" in bloody letters to bring the point home or "we make nukes, call fbi" or "never quit, there are >!goats!<"