Remember in Season 4 after Adrianna found out that Danielle (the first FBI agent that posed as her friend) was supposedly hitting on Christopher and she ended her friendship with her they sent in this current female FBI agent. They told Adrianna that she can either become their informant or become the defendant in a drug possession case -- I think that Danielle was around her when she was doing drugs. Then, they told her that when she made bail after being convicted, that she can explain to Tony why she brought an undercover agent to his home for Sunday dinner -she had brought Danielle there once. Then, after they told her that Adrianna threw up on the conference table. So, I think she figured she was trapped but I bet she would have been better off fessing up to Christopher or Tony from the beginning. She was set up by the FBI -- she thought Danielle was her friend.
I feel so bad for her now and I honestly think she's going to end up dead -- either by hurting herself or Tony hurting her first if he finds out.
Linda