He didn't really agree to bring Danny Pink aboard, it just sort of happened. Just like most of the other companions that boarded the Tardis. A chaotic mess of happenstance that ended with them rushing through the doors to escape being murdered and he'd watched the man stare up in shock at the spinning rotor above them while him and Clara moved to the controls to steer them into the vortex to get somewhere safe.
"It's…" the man began stuttering, finger raised and giving the room a quick wave of his arm before his eyes settled on Clara turning a wheel and pressing a knob, as though she'd been doing it her whole life. "It's…" Danny began again, reaching out to grab the outer edge of the console space as they shifted sideways.
Clara laughed and nodded as she hit a lever and gestured so the Doctor would drop his elbow onto a large button with a chuckle as he eyed her and then passed a glance at the man still staring. Normally he enjoyed the looks on their faces and the stammering that tumbled from their lips, but Danny doesn't look to him for the answer – he looked to Clara and something about that stung two spots in his chest.
"it's bigger on the inside," the Doctor barked roughly, waiting for the other man to snap his gaze to his and recoil slightly against the stare he was offering.
They level out and Clara smiled to her friend, "It's the Tardis: sort of a spaceship; sort of in space." Then she widened her eyes and walked to him, reaching out to give each of his arms a light squeeze to tell him, "Danny Pink, you're in space."
"No," the man told her firmly, then he breathed a laugh and repeated with a shake of his head, more out of exasperated wonder at knowing the truth, "No!"
"Yeah!" Clara assured and she looked back at the Doctor to catch the way he turned away to avoided meeting her eyes, knowing she could read exactly what was behind them. Clara would be able to see the jealousy and the uncertainty in them at having this man inside of his Tardis; this man Clara was comfortable with and had taken charge over.
"Does it have a toilet?" Danny asked with a finger raised before he tilted his head into his lifted hand to scratch awkwardly at the back of his neck, whispering, "That wasn't really… I don't have to… I just…"
The Doctor strode towards them, hands shooting deep into his pockets to nod at the other man, "Toilets all over, toilets of all sorts types and in all colors – have a look around," then he added slowly, "Danny Pink."
Exchanging a glance, the two men both looked sideways at Clara before Danny smiled and slowly walked away from them, out into the first corridor and it was only a moment before they heard his exclamation of surprise. The Doctor nodded and turned away from Clara to say, "Found the pool," then he added under his breath, "It's always the pool."
Clara eyed him, making his way back to the console to check their settings and make sure they were safely adrift in the time vortex while they came up with a plan of attack before they fished Danny from the bowels of the Tardis. She sighed, waiting for him to look at her and when he didn't, she hissed, "Ok, what was that?"
He raised a thick eyebrow and responded lightly, "What was what?"
Pointing, Clara accused, "You gave him a look; I thought you said it was ok."
Finally turning, the Doctor shook his head and growled, "I didn't give him a look – no more than anyone else who comes onto the Tardis," then he lifted a finger to add, "And you know that."
Narrowing her eyes at him, Clara made her way over to the center console, glancing momentarily up at the time rotor before shooting, "Don't give me that; you've still got that look on your face, like you're displeased. If you didn't want me to bring him along…"
He waved off her words with a simple, "Couldn't be helped, running. Stopping would have meant dying and we can't have dying, at least we try…"
Clara cut him off quickly, with a roll of her eyes as she asked, "Then what's wrong? Why don't you like him?"
"Because," he told her simply, toggling a switch in front of him before shifting away, but Clara followed, arms crossing over her chest as she watched him focus on the controls, trying to avoid her; the way he had been for weeks, as if even her being on the Tardis were annoying him. It was beginning to frustrate her.
She came to stand beside him, repeating lightly, "Because…"
The Doctor glanced at her and his lips pressed tightly together before he looked up towards the corridor to respond in a whisper, "Because of the way he looks at you."
"Looks at me?" Clara laughed, arms coming down as she turned and bumped his shoulder with hers, gaining a small grin before his frown returned.
"Like he…" He paused to shake his head, but Clara moved in closer, grabbing his arm and he blurted, "Like he'd gladly take you away from all of this." He stared at the console in front of him as she remained silent at his side. "Like he'd gladly give you a better life than this – a safer life than this. And sometimes," he trailed, eyes closing to finish, "Sometimes you look back the same way."
He knew she'd narrowed her eyes at him; knew she was studying him and she was working out what was going on inside of his mind, so when she slowly said, "And that bothers you," the Doctor already knew the question she wasn't asking – why is this bothering you? And he knew she knew the answer.
"I know you're not mine," he allowed softly, "I know you're not mine to keep – you're simply joining me for a time in the Tardis to travel, but…" he closed his eyes and then looked up at her, catching her by surprise because he'd done well in his campaign of avoidance with her since the regeneration. "Do you want to leave?"
"No," Clara laughed, reaching up to touch his arm and cringing when he slipped away, taking a step to their left to hit a button and check his screen. "Doctor," Clara said simply and when he turned, it was with an intensity in his eyes that froze the words in Clara's mouth.
"I," he began, and she held her breath, watching him struggle with what he wanted to say – what he needed to say – and she moved towards him slowly, hand coming up to slip over his hand, gripping it tightly as he half-whispered, "I know you're not mine," he repeated, "But that man reminds me that one day you will want to leave. One day you'll want to start a family, or you'll want to avoid having your head lopped off and stuffed into a box, or having your body crammed into a cyber suit, or tossed into a vat of poisonous chemicals and I…"
Smiling, Clara finished, "You hate endings," she smiled, reaching up to brush her fingers through his hair lightly, watching his eyelids flutter at the contact before she nodded, telling him, "I know."
"I love you," he breathed.
Hand landing on his shoulder, Clara blinked several times in confusion just before he slipped out of her grasp and went to punch at buttons on the console just as Danny returned with a loud whistle and a clap of his hands, asking the Doctor, "So, time, space, yeah? Could we go for a spin? Show me what this thing can do?"
The other man came to stand at her side and she jerked against his elbow on her arm, trying to give him a warm smile as she looked over the glowing instruments in front of her before looking across the tubes at the man now gruffly explaining time travel to Danny. Explaining it to a man who could one day whisk her away from him because, she knew, the Doctor would put her life and her happiness above his. And because he knew, one day, she would leave.