My school had 5 minutes between classes and was fairly large. Making it to the next class in time was challenge enough without battling for a stall, if there was even a bathroom on the way.
My school had 5 minutes and wouldn't let you bring your backpack in the classroom (they claimed it was for fire safety). Later learned from my sibling they dropped it down to 3 then reverted it because students kept showing up late. They couldn't get to their lockers to pick up the stuff for their next class and actually make it to class on time. Public schools are a nightmare.