Am I allowed to go to the bathroom in the middle of the frq?

Today I took my first AP test and people where in and out of the class during the free response question and we where not allowed to use the restroom during the break. I was just wondering if this is allowed because it seems a bit backwards to me?

You’re only allowed after you finish it early I believe and at my school you’ll have an escort to the bathroom being one of the proctors so they would know whether you cheat or not.