18: Sinner

The Doctor stood with fire in his eyes, no hint of remorse or apology. "I gave you your one warning."

The aliens in front of he and Bill were tied up, laying in a heap on the floor. The hisses that emitted from their mouths sent shivers down Bill's spine. Slowly, she reached a hand toward the Doctor and squeezed his arm. "Doctor...they're helpless."

He turned to her sharply, and for a moment she was almost afraid of him. "They had their chance at redemption. They knew what I was capable of."

Bill let her hand drop back to her side. "Apparently I didn't."

The Doctor's eyes softened, just for a moment, before they turned cold again. He was halfway to the nearby TARDIS before Bill could even blink. She followed him only after throwing a pitiful glance at the captured aliens, huddling by the wall of the shaking, jerking ship. In the distance, the sound of the first bombs went off. Any second now, the Doctor's plan would finish and the whole ship would blow out of existence. Bill felt new tears spring into her eyes at the thought.

The Doctor sauntered up to the Console and put his hands on the panels, bending his head down. Bill slammed the door behind her.

"What is this? Why are you being so cruel?"

He turned back to her, eyebrows furrowed. "They're murderers. They appreciate profit more than life. I told them what would happen. I told them not to cross me."

Bill wiped her eyes furiously. "Some of them are practically children."

The Doctor took a step toward Bill and she felt herself inadvertently shrink back toward the TARDIS doors. "Sometimes difficult decisions have to be made. Do you think if I let them live they'll all turn good? That I can just tell a beautiful speech and everyone will live happily ever after?"

"That's your job, isn't it? You give lectures and change people's minds."

The Doctor let out a small laugh. "I wish that actually worked. Believe me, I do. But I've been through this before. It's only a matter of time before they forget everything and start again. Isn't it better to cut it off at the source? Stop it before it goes too far?"

Bill shook her head. "They're not the ones going too far right now, Doctor."

He let out a shaky sigh and turned around, biting the nail of his thumb. Bill looked at the floor and shut her eyes. "Listen...I'm not asking you to forgive them or whatever. I hate them, too. And I know it's not 'sinking to their level' to punish someone who did something awful. But Doctor...you're always the one talking about mercy and compassion. What the hell has gotten into you?"

He replied with a mutter too low to hear, so Bill pressed forward. "What was that?"

He spun around, dropping his arms to his sides. "Compassion doesn't work, Bill. It's a con. You know what compassion gets you? Hurt. Or grieved. Or killed."

He didn't see the slap coming until he was bent over, the left side of his face stinging. Bill hovered over him, frustrated tears in her eyes. The Doctor rubbed his cheek and looked up at her with wide eyes. "Bill!"

Bill's voice softened as she took hold of his arm. "Listen, Doctor. You have a choice to make. I don't know what's gotten into you today, but I will not let your cynicism get people killed." She creased her eyebrows at him. "Be a Doctor."

He slowly straightened himself, eyes going watery. "What is wrong with me?"

Bill sensed a long introspective moment coming and pulled him roughly to the door. "Ship's about to explode. We've gotta go now."

The Doctor hurried to the door but paused for just a second and turned to Bill. She merely pushed him along, shouting, "Go!"

Later, when the ship and all of its inhabitants were safely tucked away on a prison planet a galaxy away; when the Doctor was staring pensively up at the Time Rotor and Bill was sitting casually on one of the flight chairs flipping through the TARDIS' copy of The War of the Worlds, he finally spoke again. "Thank you."

Without looking up from her book, Bill replied, "I won't always be there when you get all authoritarian and extremist."

"I know. It's not your job to reign me in. I'm sorry."

Bill set the book down and looked up at the Doctor, whose fingers were tapping restlessly on the control panel. "What happened?"

The Doctor glanced at her, then turned down to his hands. "Something set me off. I've...I've been in a war before. Maybe they reminded me too much of myself. All the things I did."

Bill's eyes widened for a moment, but she stood and went to the Doctor's side with warmth on her features. Playfully, she fiddles with one of the less important buttons on the Console. "Maybe you need to talk to someone. Or figure out some healthier coping mechanisms."

The Doctor turned toward her halfway. "Coping mechanisms?"

Bill shrugged. "Yeah, like, things you can do to help you get through stuff. Things that aren't bad, I mean."

The Doctor nodded, and Bill watched him pensively for a moment before placing her hand on top of his. "I don't mind helping you out. I just...don't wanna be your therapist or anything." She let out a chuckle. "Not that I know how."

"I know. It's not fair for me to ask that of you."

They shared a smile and Bill took her hand off of his, pacing around the Console. "So...where to now? Nardole's probably wondering where we are."

The Doctor rolled his eyes. "Nardole can wait. I'll take you back to the university, though. Or home, if you want. Where is home now? Did you get a place with those friends of yours?"

Bill raised her eyebrows. "Where are you going?"

He smiled softly. "I have an appointment to make. You're right. I need to take some responsibility and face my demons. Can't be running around the universe threatening everybody, can I? The history books will start confusing me with the Daleks."

Bill smiled at her professor proudly. Perhaps sometimes everybody could be a bit of a sinner, or an arse, or whatever they wanted to call it. And a lot of them were bad, and maybe didn't deserve any remorse. But maybe all that some people needed was some help. And maybe a smack in the face sometimes.