More information: http://wp.me/p1SfP0-Z8
This is the last part of the Run For Your Life Mission in Hitman Absolution. In it you escape the apartment building and maneuver the train station to catch a train. This guide explains how to complete this mission on the hardest, purist, difficulty. It does not explain how to complete the different challenges in this area.
When you start go to the right through the door. Immediately go up to the counter and take cover behind it.
A police officer will show up, but also leave eventually. It is best to wait him out. Once he also leaves the adjacent room stop hiding behind cover and you can walk out of the front door. Keep following the walkway until you get to a big crowd of people. When you are in a crowd of people you can't be detected by nearby police officers. Exit the big crowd and go into a smaller crown near the right edge of the platform.
There are 2 police officers ahead. The one closer to you will eventually walk off to the left. The other one should turn around and look the other way whilst the other police officer isn't near him. When both those conditions are met start walking straight ahead neat the edge of the platform towards the ticketing office. On the right side of it you can walk along a ledge.
Follow the ledge until you get to a window. Climb into the window and immediately crouch. Walk towards the other side of the ticketing office and turn around. You will see a ladder. Climb up the ladder and approach the console and perform the action required. Then turn around and hide in the big box until the guy that is in the room with you leaves the room. Follow him out of the upstairs area of the ticketing office and go into the crowd right outside of it.
There are 3 police officer patrolling around and one standing next to the wall to the right in the image above (partly hidden behind the pipe). Don't worry about the last guy. One of the patrolling guards has a much longer patrolling distance than the other. Wait until he has just left the little area you are in and then wait until the two police officers patrolling right in front of you have just left your side. Then walk up to the small crowd ahead.
Wait until the same two police officers have walked past you in the opposite direction and walk into the next crowd in front of you.
There is one more police officer ahead. Wait for him to walk towards you and walk out of the crowd on the left side. He won't notice you. Walk down the stairs and into the big crowd.
Make your way to the back of the platform whilst staying in the middle of the crowd and making sure to avoid the police officer patrolling in the crowd. On the far end is a gaming machine which you can use to hide. Wait until the train arrives at the platform and walk towards the closest entrance to you. The crowd will start walking towards the train too, so use it to keep you hidden from any police officers. Once you enter the train it is the end of this part and indeed the mission Run For Your Life.