When the trucks arrive back at the firehouse after the first call out (at the bowling alley), the two trucks and the chief's car drive in and the third door is closed and that lane empty. As the camera changes to Dawson getting out of the truck, the doors behind her are closed. When the camera goes to an overview, all three doors are open, the ambulance is suddenly there with people getting out, Engine 51 is parked in front of it and all three doors are open.
Otis slips and falls onto his back. In the next scene, he is on his belly in the same spot.
The term hostile work environment has been used in the past in the series when Jones was at 51. What the interim chief did towards Otis and other subordinates would certainly constitute a hostile work environment, which as the chief he was liable for. Since the union president was a firefighter there, a complaint would certainly be filed. Additionally, in public safety organizations, officers cannot give orders they know to be improper or unlawful. The interim chief's order to send firefighters into 15 degree weather to wash windows would needlessly endanger their health. Such an order would add to the evidence of a hostile work environment.
Otis is trapped by an interior door. Interior doors are far flimsier than exterior doors. Many times on the series the firefighters use a reverse kick to open exterior doors. Otis could have easily done so but did not.
Boden is seen addressing the staff in uniform presumably at the beginning of their shift. Since he was going on pre-approved leave, there would be no need for him to dress in uniform just to make this brief announcement. In reality, he would not have reported for duty at all, as his leave would have begun with that shift.