He took the leaf, and then ground up a bunch of other leaves (with spittle to make it a pasty thing) and rolled them into the first.
He then started looking for a way to make fire.
The Boiler? They're sending you to the Boiler room to convert your bones into energy to fuel the school's machinations? And whatever is left of your ashes will be pressed into a brick? And once they gather enough bricks they'll rebuild the school?