Suspect

Liam Neeson lived in a Washington, D.C. homeless shelter for two days, to prepare for his role.

At 1:23 into the movie, when she is checking keys against file cabinets at the Justice dept., the key won't fit into one of the file cabinets, then the key fits the very next one. This is minor but would not happen. Since the file cabinets are identical, they key would at least FIT the lock (though it wouldn't turn the lock mechanism) unless it were the correct key. For example....all Master Lock keys (of the same sort) will fit the intended item perfectly - it just won't unlock it unless the pins match.