Sam’s managed to sleep pretty steadily, once he finally went out. Not to say it’s been a very peaceful sleep, but he’s never come far enough out of it to properly remember it. It’s all fire and monsters and blood and yellow eyes and people screaming, and then a moment of blissful nothing where he’s probably half-awake, not cluse enough to the surface of awareness to see through but not deep enough to see anything else, either, and then it all starts back up again.
Still, it’s sleep, so it’s... it’s something, anyway.
But the sound of voices drags him out of his current dream (it’s some woman he doesn’t know, and she’s screaming and running from something with too many glowing red eyes, carrying a baby and running and she’s barefoot), sets his heart racing and he snaps awake, sitting bolt upright with one hand reaching under the pillow where Dean had left a gun for him (not that he’d need it, since Dean has a gun, too, but maybe he’d fall asleep, and what if Sam did need one?) before he sees Jo in the doorway and his brother in the chair nearby and his breath rushes out all at once, and as soon as the air’s out his muscles go from tense and ready to defend himself to limp and useless and he sort of melts back down against the pillows, sheepish and a little bit sulky, like a kid caught doing something stupid getting cranky because he was caught.