Actually i've found that a mine planted in the doorway you need to sneak Maria out of makes the the only way out of the bordello to be via the front door. That means you need to kill off the kingpin faction before you can free Maria. The upside of all of this is that Tony doesn't seem to have a faction in WF 1.13 so it doesn't really matter.

There is a guy patroling the area (that guy tends to spent a lot of time in the kitchen... it is quite possible to put another merc before the door to block him in the kitchen), he might have seen you on your way out.

i did not even get the quest from angel this time (squadleader/optimist imp) -> shot them both)