Do people really think IRL military tactics apply to a world where people can just tank gunshots at pointblank range? That fact already invalids most common squad level military tactics. Involving things like superhuman physical abilities to just run faster, jump higher and outright magic such as Hasumi blowing up a tank with a single bullet and most Earth level tactics are null.
And it's not like students can't coordinate, considering Arius, SRT, Prefect and JTF clearly have some level of coordination and Kaiser robot PMC who are adults, despite having common loadouts as normal grunts on Earth so I assume similar tactics as well, regularly jobbed to students and can only doing overcome the difference in massive number advantage