A question about a recipe: Una Pizza Rustica e Autentica for Sophia Loren

I have a question about step 10 on the recipe "Una Pizza Rustica e Autentica for Sophia Loren" from pierino. It says:

"Now work fast, really fast; ladle sauce in a spiral pattern starting from the center outward in a circle over your soon to be pizza(s) and then apply thin slices of buffala. Slip that disc of dough upon the stone. Slam the oven door or grill shut. And then you shut up, because I don't want to hear your mouth right now."

we do pizza night once a week. constantly on a quest to create THE ULTIMATE PIZZA. i love this recipe. thank you. i was wondering if you have ever experienced mozzarella giving off water in the heat of the oven? am i do something wrong?