“..To such a degree that they could see the Sibilis and protect themselves?” Emily interrupted.
Technically speaking, what he was doing was expressly forbidden by his people, but providing he didn’t make a habit of it, what the Time Lords didn’t know couldn’t hurt him. Besides, Emily had found the source of the Sibilis which could potentially halt another outbreak. There was no way the Doctor was going to let her die.
“And no one has responded?” Emily asked, aghast at the sight in front of her.