Why does Agent Smith get scared in the final confrontation with Neo?

Explaining Film on Instagram: "The iconic “Burly Brawl” scene in The Matrix Reloaded (2003), where Neo fights dozens of replicating Agent Smith clones, combined practical stunt work with groundbreaking CGI. The sequence was filmed over 27 days on a constructed playground set, using stunt doubles for Hugo Weaving (as Smith) and Keanu Reeves (as Neo) performing real choreography and wire-fu martial arts for the initial phases, when fewer Smiths were involved. As the number of clones grew to over 1