I didn't notice it before reading the Uproxx link above, but if you watch it again, she walks in, she see's Blake... looks up at Frank, Frank says something like "here we are", then she just kind of exhales and looks up like she knows the gig's up.

I want to believe it's just misdirection, especially since Blake didn't say anything about her, but if it's not, I wonder if Frank suspects it at all. Seems his only loyal friend is Nails.