The Master waited until he was pretty sure Brant was safely out the door, holding himself perfectly still, barely even breathing, because he really, really wanted to call Brant back, and was afraid if he opened his mouth he would.
Then he threw his mug, full strength behind it, against he kitchen, with loud growl. That felt ridiculously good, the rage he'd been sitting on pouring out of him. He promptly started trashing the entire place, hoping he'd get lucky and wear himself out. Eventually.