When I wanted to enter the rivet city for the first time(the main story line) I talked to crow and bought the combat armor and motorcycle helmet.then I went to look for a way to enter the town. I saw Carlos and gave him some water but I didn't see the intercom next to him.I tried to find a way under water until I found Pinkerton and I was disappointed because I couldn't find a way.and then when I searched Google I found out that I had to talk to the intercom.and when I met zimmer I found out that I had to meet Pinkerton for that quest.