[She nods to Jack when he throws her the glance. Martha knows she's saying too much, and she figures if she stays here as an unobtrusive guard for Jack and Ianto, then she won't have to say anything to anyone else. It's a win-win situation in this joke of all jokes the wardens have thrown at them.]
[And maybe if she stays close enough, she can find out more. She's an excellent eavesdropper after all.]