Clara, Ohila and others in “Hell Bent”

One question. And you will answer: How long was the Doctor inside the Confession Dial?

We think... four-and-a-half billion years.

He could've left any time he wanted, he just had to say what he knew. The Dial would've released him.

Four-and-a-half billion years?

If she says so.

No! Why would you even do that? I was dead! I was dead and gone! Why? Why would you even do that to yourself?!

I had a duty of care!