Swing

You manage to jerk your arm forward in the moment before your hand releases the rosario, giving it enough momentum that it swings from your fingers and flies through the air. Fortune smiles on you, and the pendent not only hits the bare skin of vampire-Emily's chest, it also falls into the valley of pale cleavage her dress exposes and winds up lost in her bra. Judging by the amount of hissing and swearing she does--not to mention her frantic clawing at her chest--this causes quite a bit of discomfort. It also provides you with more than enough distraction to shake yourself loose from her spell and sprint away, out of sight.

You've escaped! You run across the parking lot, heading straight for the car before remembering that Emily drove and that she still has the keys. And she now has your rosary. There's no way you're going back for either.

You look around the deserted parking lot, filled with unoccupied cars clustered in the one open space between the woods and the Conference Center. You wonder where you should go from here. You know from the map on the back of the invitation that the entrance to the estate is somewhere behind you, to the south. If you decide to escape on foot, you could head out that way, though it would be a long walk. The Conference Center and Library, of course, lie nearby to the east. That's where Emily is for now, but it's also where her friends are--the only other people at this party you even sort-of know. To the north, unseen through the trees, is the old mansion, where you read some kind of occult ritual was supposed to be reenacted. To the west is nothing but wilderness trails: a good place to get lost, though maybe that's what you need.