Rose hadn't expected to meet strangers in the TARDIS.
"Another one," the blond man in grey said, with the air of a disgusted entomologist. "Why does he have to keep --"
"Don't worry about us, dear," the blonde woman in blue told Rose. She had a perfect smile. "We're just keeping tabs on things."
"Should I know you?"
"No."
"Should I tell the Doctor?"
"Probably better not," the woman said, with another dazzling smile. "It'd just worry him."
"But if you're Time Lords --"
"Us? No." The man snorted. "We're . . . agents. We handle irregularities."
"And we're gone."
And they were.
---