Why did Merrimen's girl tell him "I did what you told me" after sleeping with Nick?

In addition to getting the phone number, she also told Nick which bank they were going to hit. Merrimen wanted to make sure they were set up and stalled outside the bank, that way they could hit the Fed without Nick and the other LA County Sheriff deputies getting in the way.

Bonus question: Could honestly go either way. Girls in a strip club, especially with alcohol involved, look way different than they do in the light of day and more natural lighting. But Big Nick also could have done his research and already knew she worked at that specific strip club (thus the reason for him being there in the first place).

This was confusing to me too since they made some strong implications but didn’t lay everything out crystal clear. It seems like the police officer was trying to provoke and agitate them as much as possible by literally sleeping with the stripper who was this guy’s wife. Or girlfriend. But then, the movie tries to flip the script by showing that the guy was in on the whole thing and had asked his girlfriend to do so in order to potentially get information from him for the heist. What info? Not sure. Maybe a tracer or where they will go? Obviously, the whole scene was very tense since you would expect someone to flip out in rage when he gets home and the guys there with his girlfriend. But he plays it cool as a cucumber, maybe too cool, since it ends that he’s trying to keep things cool because he knows he doesn’t want to be provoked which would give away that they are planning to kill people and to do a heist which he gives away by being so cool .