Visible crew/equipment: When the agents arrive at the Four Horsemen's apartment to arrest them, in the shot where Dylan exits the car, the reflection of the boom mic is visible in the other car's window. Try not to be confused with the bird flying around in the reflection - the mic is still visible next to the bird. (01:15:00)
Visible crew/equipment: When the car chase happens on the bridge, at the point just before the car comes to a stop upside down, the roll/safety cage can be briefly seen. It can also be seen as the car explodes just after Mark Ruffalo put his hands on his own car.
Answer: The mirror was inserted at an angle, so that the reflection was the ceiling and not what was in front of them. It's the same principle for how periscopes work.
Bishop73