Clara Oswald you gorgeous ruthless bastard,
This is one of my favourite Clara scenes for this exact reason. We see her being good so many times, almost unbelievably conscious of what’s the right thing to do. But this? This is Clara under pressure, and pressure always reveals the real Clara. Sometimes it’s that she’s scared, but sometimes, like this, it shows that she’s got the sort of dark ruthlessness inside of her that the Doctor shares.
She’s not perfect, she’s not even always nice, and that’s what I love about her.