Theres a elevator shaft with 2 lifts stuck at the bottom. You can move one of them with the electric charge. Shoot the motor twice so it goes high enough and then jump into the space that was under that lift. There will be a open elevator door with 2 guards. Its easy after that.
BTW you get to the elevators from the room you fought the 1 armed giant clown. --- When all else fails, play dead.