What are her motives? Simply because she was there and is afriad?
There's also this little thing called morality, which some (admittedly few) people possess, and while tends to be offended by the government committing murder. She's new, an outsider, and hasn't experienced the corrupting influences of institution life, so she's in an ideal position to be a whistle-blower.
I get what people are saying about Torchwood reacting rather than acting in this episode, but the only alternative would be an implausibly quick recovery from the devastating attack, which would undermine the drama of their predicament, or dropping the attack altogether, which would lower the stakes too much.