A guard is posted just Fut 14 Coins outside the first door. Knock him out and kill him. Pick the restroom door lock, and the doctor will get on the train. Talk to http://www.mmo2k.com/FIFA-14-2515/ him, then leave the train.
Go through the green double doors at the far end of the station. Kill the patrolling guard, then head up the stairs. Follow the hallway to the left, destroy the cardboard boxes with your knife, then go through the hole in the wall. Drop down quietly behind the tank. Wait until the guards are done talking, then take them both out.
Go through the double doors. Knock out the guard on the lower floor, then quickly get the other as he climbs the stairs. Kill them both, then climb the stairs and jump to the duct that runs along the wall. Go through the only open door, deal with the guard, then jump through the open window onto the ledge. Follow it around, then drop down near the control station.