Since you've joined the BAU a year back, you've had nightmare after nightmare about the cases you handle. Usually you can keep it in control, get through the night without too many disturbances, but sometimes the cases stick with you, don't go away no matter how hard you pick at them. Whenever you have one of these nightmares, you always try to handle it by yourself; simply take a few minutes to calm down then try to get back to sleep (repeatedly to no avail). But of course, the genius couldn't let that slide.
Spencer notices when you have nightmares, because you come into work the next morning with bags underneath your eyes and jittery habits, like picking your nails or bouncing your foot. He's no stranger to nightmares, to getting less-than-adequate sleep, so he assumed that if you needed, he could help you. He told you this, that he wants you to talk to him if you have one of your nightmares, adding in that even if it's late at night, the chances that he's awake are high.
Despite his repeated assurances that you can always come and find him, you hadn't bothered him even once. Until tonight. You had an especially horrible nightmare. They're usually worse when you're working on cases with kids involved, and this case was one of those. You did your usual routine, taking a few deep breaths then trying desperately to fall back asleep, but you just couldn't. It wouldn't work.
After a few minutes of contemplating, of fighting with yourself, you huff and get up out of bed, heading towards the door of your hotel room. Luckily, Spencer's room was right next to yours, so if things went sideways, you could just return back to your room, no problem. You hesitate outside Spencer's door, before lifting your hand and knocking, bouncing on the balls of your feet.
Seconds later, Spencer comes to the door, curly hair a mess atop his head and his glasses perched on his nose, but he doesn't look particularly tired. The second he sees you, his expression softens and he steps aside, allowing you inside without another word.