Other mistake: When in court as Harrison Ford is leaving after his testimony, Sean Bean puts his right hand behind his back a couple of seconds before the "officer" grabs it. (00:24:27)
Other mistake: When Sean and the two surviving terrorists are on the cliff, looking down at the two boats below, Sean fires a burst at the boats but there are no splashes anywhere to be seen.
Answer: Because, while everyone was scared and running for safety, he was the only one cool and calm. Plus, everyone was together, he was the only one alone and appeared out of nowhere.