He might find it hard to grab anything with a Monte Blanc pen shoved in his earhole.
Truthfully.. if I was armed with a hand gun this is one situation in which I'd shoot. This person is not attempting robbery by grabbing your ankle, you are in a vulnerable position. I wouldn't flame a woman for unlimbering hot lead in this situation and therefore.. neither would I a man. If it happened to a woman you'd think "rape in progress", and that is grounds for deadly force.
You need a whole lot of hands to stand up hold the door, draw your pistol and pull up your drawers all at the same time, not to mention you are a sitiing target (literally).
I doubt very seriously his compatriots would stand still flat footed while you perforated said attacker with whatever means at your disposal. You knife him they may come through the door, you shoot him and they will likely flee. You don't know how many there are or what they look like. Don't miss, the 4 rules still apply.