She could feel his shock. She had thrown him off. He had to scramble, make new plans. He wasn't prepared. Maybe she wasn't supposed to be here at all. Or this location. He thought she'd be taken from the streets. He didn't expect her to come for him. He didn't expect her to know that to kill him, both hearts had to stop. There was something different about him. He wasn't human. But he still had feelings. Glee in the chaos. Excitement at what was happening. His game. He saw someone else in her. He was too excited by her arrival. She wasn't here but she saw the boards. She got bored and read them. She knew who he saw.
Rolling her eyes at the comment on politeness, River just cocked the gun again.
"Hello."
And she shot two more shots at the Master without blinking, each aimed at a heart. She heard them. The heart beats. Felt them. Felt his insanity. His madness. Felt his excitement and glee. And he would go silent. And Simon would be safe. And the other one. Vaguely familiar. Didn't matter. Two people saved in the crisis. No more taken by him. The brainwashed free.
Sensing someone move behind her, River's eyes narrowed and she pivoted and kicked them in the throat before focusing on where the Master had been standing, reflexes on alert, poised to fight any that came at her from behind or the sides. She was a weapon but at least she was able to channel it. Because Simon needed her. Because he was alive and would stay alive because she wouldn't let him die.