"The supply closet?" Castle muffles a laugh with his hand, watches both Gates and the offended cameraman shoot Beckett a glare as the Captain escorts him into the break room to let him gather up the rest of his equipment. Beckett misses it completely, eyes on her paperwork.
"How did you even know that was there?" Castle continues, plopping him into his chair next to the desk. "Do detectives even have to get their own supplies? Beckett?" He leans further into the desk when she doesn't look up.
"Castle," she leans an elbow towards him, eyes finally coming up to meet his. "Shut up and let me finish so we can go home."
"I can finish you in the supply clo-"
Her glare cuts him off. He huffs back into the chair as she goes back to the paperwork but doesn't relent, chin coming to rest in his hand as he props his elbow up on the table. "But really, what have you done in that supply closet?"
No response.
He leans into her space again, leering. "Have you ever wanted to lock me in that supply closet?"
"Oh, plenty of times," she says, pen still running over the page as he leans even closer. "That first year you showed up here especially. All those times you stuck your nose into my business what I wouldn't have given to put a locked door between the two of us." She looks up again, smile flirting at the edge of her lips as he scowls and leans back into the chair.
There's silence for the next few moments as she continues to write and then the harsh grate of a desk drawer opening followed by the empty click of a stapler. She frowns at the two pieces of paper in her hands and looks at Castle.
"Do me a favor and get me some staples?"
He opens his mouth in question but closes it before saying a word, gestures towards the supply closet and back towards her and she raises an eyebrow, lips quirking up.
"Staples?"
He's been in here for at least 5 minutes.
The thought enters his mind that she might have actually wanted him to get staples, and he starts to look around the room hurriedly to see if he can find them and get out of there before making a fool out of himself when the door opens and a flash of hair whirls in his face, locking them in.
She turns to him, grinning, and he breathes a sigh of relief. "Finally. Jesus, I thought-"
She cuts him off with her mouth, and his hands jump to her waist as she pushes him back into the shelf. He grunts as his back clatters against the supplies behind him, the firm press of her body melding to him and knocking some aerosol cans to the floor.
She pulls back from him, breathing harshly, eyes suddenly like fire. "Shhhh."
"You're the one who-"
She cuts him off again, tongue tangling with his and one of her hands grabs for his from around her waist, dragging it down to the seam of her jeans and pressing hard. She rolls her hips against their hands, guiding him and letting him take control at the same time, biting her lip as she grabs his shoulder with her other hand. The rough glide of her zipper cuts through the tiny whimpering sounds she's making as he slides his hand between her pants and underwear, teasing, and her nails begin to dig into his shoulder-
"What the hell?"
They both freeze at the voice outside as the doorknob rattles, and Castle has a brief flash of the door opening and Gates catching them with his hand quite literally down her lead detective's pants when the detective in question cants her hips into his hand, opens her mouth against his.
"Don't you dare stop."
He chokes but works his hand quickly, fingers slipping into her underwear and then against bare flesh as voices outside debate where to find a key. He can almost see it become white noise to her as her eyes glaze over before she blinks slowly once, twice; gripping his shoulder as she drives herself into his palm.
His name gets caught in her throat when her whole body goes rigid and she breathes out a stuttering sigh of relief against his face, hips still moving as she comes down. She presses a kiss to his jaw, hand clenching and unclenching at his shoulder to the tune of herself around his fingers before she pulls his hand free, throwing a roll of paper towels at him.
"Clean up," she whispers, buttoning her pants, and he realizes the voices have faded for the moment. He rips off a sheet, wiping his hand clean and shoving it into the pocket of his coat before looking up to see her putting her finger to her lips and darting out the door.
He whispers her name in a panic to the empty room, rushing for the door just as he hears the voices getting closer again along with the echo of the stairwell door next to the closet. He curses, wildly looking around for any kind of escape as he hears a key insert itself into the lock and he grabs the nearest item from a shelf, putting on his best nonchalant face as the door opens and two uniforms stare at him curiously.
"Oh, thank god!" He staggers out, hugging them both. "I thought I was going to be trapped in there forever!"
The two men look slightly taken aback but one of them is staring even more quizzically at his right hand, and Castle looks down to see himself holding a telephone receiver, cord trailing on the floor by his feet.
He looks up helplessly. "Detective Beckett just needed a new... um, phone. Hers stopped... ringing?"
He slips past them, shaking his head at his own terrible excuse as he makes his way back across the bullpen. The elevator doors slide open and he turns his head to see Beckett stride out, looking fresh and not at all like she just got off on her boyfriend's hand in a supply closet while he stands there dumbly holding a phone receiver.
She meets his eyes as they both approach her desk and then looks down, raising an eyebrow, but extends her hand to accept his offering before setting it down. "Thanks."
The bullpen is emptying out as she pulls her chair out to sit, and Castle whines in the back of his throat as he shifts uncomfortably from his position next to her desk. She flicks her gaze to him as she scoots her chair in, nudges the phone across the desktop.
"Don't worry, Castle," she says, casting her gaze around their now-half-empty surroundings. "I am going to actually need staples eventually."