(You really have little choice here.)
If you ever give a boy a time limit in the bathroom and make a rash declaration like, "You have one minute, and then I'm coming in!", be prepared to actually do it. And then see all the other boys scatter like insects.
Boys' bathrooms are not pretty.
And just in case you are in a situation where a defiant boy is sitting in your office, not doing the work he is supposed to do, don't expect that you
will get your own work done. I think there is a scientific reason for this, but I'm not sure what it's called. Maybe Einstein would know.
Get the picture?
I'd much rather have been here today.