Continuity mistake: At the beginning of the episode, a bunch of money falls from a building. Of course people are grabbing it but when the First Responders show up, everything has miraculously been cleaned up. No money to be found. With the amount that has fallen and the chaos, there would likely be some left over. The street is squeaky clean.
Continuity mistake: When all the firefighters and EMS teams are coordinating in the big dirt parking lot with the view of downtown LA behind them, the sun changes several times. Its either later in the day or earlier, depending on the angle. Look at the scenes with Athena talking to another character. The sun is in front of them. Cut, and the sun is overhead.
Audio problem: At the end of the episode, Buck comes home and crashes on his bed. He sees his girlfriend reporting on TV. Just before the shot cuts, the reporter mouths a word but nothing comes out. The shot changes to others watching the report, and she continues talking.