Dean: Does Jessica know the truth about you? I mean, does she know about the things you've done?
Sam [seething]: No, and she's not ever going to know.
Dean: Well, that's healthy. You can pretend all you want, Sammy, but sooner or later, you're gonna have to face up to who you really are.
Sam: And who's that?
Dean [gleeful]: One of us!
Sam: No! I'm not like you! This is not going to be my life!
Anyway, back to the action: Sam disparages Dean's sacred memory of Burnt Mary, so Dean tosses him up against a support beam and hikes his tongue down Sam's throat. Kidding! I'm totally kidding. It's the women who make out on McG's shows, not the men. You people are so silly sometimes. Dean actually warns his brother, "Don't talk about her like that," before backing off to cool down a bit. He begins to stalk off down the bridge, but pulls himself up short (heh. "Short." Geddit?) when he spots the spectral presence of Constance atop the nearby railing. Dean quickly draws Sam's attention to the ghost, and the boys warily eye her as Constance first turns her head to fix them with a menacing glare before allowing herself to drop into the river below. The boys dart over to the side to see where she went, but they're looking in the wrong place, for sly Constance has actually taken control of the Impala. She activates the motor and fixes our two intrepid heroes in the headlights' beams. Neither they nor we can see her behind the wheel, of course, but we all know she's there. Constance guns it and tears off down the bridge to take out Sam and Dean, and...hey! Wait a minute. This isn't her M.O. at all. Is she even allowed to do this? Whatever. The important part is that Sam and Dean turn tail and run, and we get a very, very nice shot of Jensen Ackles's denim-clad ass in motion as they go. Woof. The boys, realizing there's no other way out of the situation, vault the railing halfway across the bridge and dive. Constance slams the Impala into the bit of railing the boys had just leapt, and the shrieking strings once more assault the soundtrack as we get bitch-slapped into the next commercial break.
Bridge. Aftermath. Sam actually managed to grab hold of a jutting length of iron on his way down, and now scrambles back up to the bridge's railing. Panicked, he calls for his brother until he spots the muddied Dean crawling out of the muck and onto the riverbank below. "Are you all right?" Sam calls down. Dean, caked with God knows what, rather amusingly offers his younger brother an OK sign while replying, "I'm super." Moments later, both boys are again on the bridge, with Dean confirming that whatever their unfriendly ghost did to control the car, it doesn't seem to have had any permanent effects. "That Constance chick," Dean manfully rages. "What a BITCH!" The boys perch on the Impala's hood, and Sam takes a moment before noting, "You smell like a toilet." Hee.