I think there is a strong parallel between Lucy and Lydia, on the one hand, and Fag and Jack, on the other. Lydia thinks Lucy is a simpleton, and, at the beginning of Act I, scene 1, Jack starts out seeing Fag like a blabbermouth who can't keep a secret, but two seconds later, Fag has quietly given Jack his "script", i.e., he is in Bath recruiting. Who's the master, and who's the servant here?