Joke, Eve Myles as Gwen from Torchwood

Martha: Jack's right. These attacks are not random. They're clinical, professional. More like assassinations.
Gwen: Except Barry Leonard was a student. Who'd assassinate a student?
Martha: Student loans company?
Gwen: Yeah, I think you just cracked it.
[They both laugh.]

- Eve Myles as Gwen Cooper from Torchwood, Reset [2.6]