"The citadel?" Martha asked, blankly, wondering if this Citadel was another prison, considering 'spent time'...maybe this alien guy was a a convict? He didn't seem particularly dangerous. She shook her head, a little wary. "I'm sorry, I haven't...it's just something that you hear, sometimes, from people around. Tories, usually, I mean. 'Some of my best friends are black!' before they reduce police brutality laws for the Met or something."

She paused, feeling a little sheepish, considering she'd actually broken one of the unwritten Doctor rules: your culture is not their culture. "I'm sorry, if you're not from where I'm from, that probably didn't make any sense."