You have many choices of moving on this floor. There is a machine gun in the room to the left. The shortest way to the elevator is to tour the cyan hallways, make it into the purple area in the north and back by the pushwall in the corner of the steel structure. The elevator is found down the corridor. After eliminating the 3 mutants, push a wall on the left side. Past it you get to look into a sinister, seemingly quiet area. Leave the 1-up unless you are very low on health. In a room behind the dummy elevators is the Gold Key. There are two entrances to the blue stone area. By the dead guards push the first secret door northward to get locked into the maze. Locate the chaingun, the Silver Key and the 1-ups, but look out for the mutants. To get out of the maze you have to pass a Grosse brother. Now start the long tour. Stop by the secret room in the south-east if you want to fight the Grosses. In the north be on the run and fight for your life. The purple area will leave you low on both health and ammo, with the Grosses on your heels. Prepare for a dreadful confrontation, locked into the secret central area! Secret doors take you to the elevator.