Deliberate mistake: When the two security guards inside Firebrand alert the other security about David being on the roof, a news reporter overhears, announces it and everyone looks up. The news channel then shows an above angle shot of David standing on the ledge within a second, but how did the news channel manage to start filming David standing on the roof that quickly or even manage to film from this angle? David going up onto the roof was entirely unplanned and within a few seconds of anyone realizing he was on the roof, there is suddenly a news helicopter from above filming the entire thing. It could not have been filmed from the ground because the news is filming an above angle shot and would have been too far away to film. This was probably done intentionally to increase the drama, but still makes little sense.
Deliberate mistake: After David jumps off the roof of the Firebrand building, it is discovered that he had been wearing a parachute, but this parachute was never visible on him at any point previously in the scene. Even when he was on the roof and after jumping, the parachute was nowhere to be seen. The parachute was too big to have gone unnoticed. It would have been visible whenever the shot was behind him and the straps would have been seen whenever the camera was in front of him.