You can describe Casino's thoughts as he makes his way into the building, skills that he is using (go to Roll20 and make your skill roll), present actions in case something happens...
Entering the lobby, Casino pauses, holding up the team's progress as he assesses the area (Awareness/Notice: 1, seeing nothing that gives him alarm, the big solo makes his way up the stairs. Pausing at each corner/landing, he peers up the next flight of stairs and as far up the staircase as he can (Awareness/Notice: 16). Once they've achieved the sixth floor, Keith moves a little slower. His fierce gaze piercing the gloomy hall (Awareness/Notice: 19) and his hand hovering near his .44 Automag...
Something along those lines is basic. Add thoughts, feelings, responses to things that I've described in my post. Reactions to other character's actions and statements... I've faith in you, Tann.
Espatier just posted with a series of "what if's" responses. I may only use a couple of them depending on how the die plays out, but at least I know what his intentions are. You can do the same.