No idea. Probably someone working on honing their special fx skills. With an improved CGI though, the technique is good. Notice the timing of the “swoop” of the tail of the helicopter just as the actors run by? It gives the illusion that it almost hit them and they narrowly escaped.
Mind you, today’s #1 best top notch CGI is going to look like this in a few years.
Example: CGI Roman / Greek / Spartan soldiers of the movies from a few years ago look fake and computer-y now. But a few years ago people were raving about their realism. Our eyes + minds adjust very quickly and see the flaws.