>Since maggie wad referring the q train
There's more trains than the Q in NYC and they have emergency phones. So my take is it was a message related to Q, which Q certainly picked up on.
My guess is the bad guys avenue of communication is comped and Halberman is warning thwm. FBI 3 maybe Ohr (via wife with SW), McCabe and Comey and DOJ is RR.
Q is verifying that he's listening in, IMO.