Yep, and that also means you cant get to the weapon upgrade station in there.

Yeah, his name is Sander, but I figured I woldnt say anything because I think we all knew who he meant. The door we are talking about is in his apartment in the Apollo square area. It is downstairs, in the same comples as Tenenbaum's place.

*spoiler*

quote

When you leave the haven for little sisters and Fontaine uses "Code Yellow" to try and kill you, her apartment is the first place you are sent. If you did not kill Cohen earlier in the game, then you have to eithe attack the dancing splicers or disturb their dancing by playing the piano or knocking over the record player. Any of these actions will cause them to attack you, and make Dohen angry. He will say he is coming down there to deal with you, and the closed door that was on the right as you aproached the dancers will open.

quote iLLmatic

Well if you don't kill Sander in Fort Frolic, what other method would you use to progress in the game?

After you finish his "masterpiece," he will come down the stairs. At this point he stands there looking at it. You can choose to fight him here if you like, but he will not attack you. He has given you the ok to leave, and the door to the Bathysphere is open.