This guide will show you how to unlock the “Ghost-in-Training” trophy/Achievement in Call of Duty: Modern Warfare II. To earn this achievement you need to reach the penthouse in ‘Mission 11: El Sin Nombre’ without killing anyone or triggering the alarm.
In Mission 11: El Sin Nombre, after you’ve been interrogated downstairs, you’ll eventually meet up with Alejandro. He will give you a mask and you can roam freely on the 1st floor of the mansion. Next, you need to make your way to the penthouse.
After you gain control, go all the way to the backyard through the door at the back as shown in the picture below.
Once you are in the backyard, climb up on the balcony shown in the picture below. Go up the stairs and grab the bottle. This will take you to the second floor.
Then proceed ahead to the hallway, and go right to the end.
Walk forward through the room and take another right turn to reach an outdoor balcony.
Jump over the railing to reach the top of the small roof. There is a ladder with some wine growing on it. Climb the ladder to get to the roof.
Hide near the roof’s high ledge-like structure. There are three enemies patrolling the rooftop, and you must proceed to the northeastern part of the roof without being discovered. Wait until the sniper walks by you. Crouches and approaches the second bottle.
Turn around quickly and toss the bottle to distract the guards in the white tank top. Walk behind him and hide as he becomes distracted.
Throw the second bottle to distract the guards in the white tank top once more, then go to the next ladder.
You’ll then meet Alejandro on the roof and make your way to the elevator shaft.
To start the elevator, hit the yellow button; when you see the first elevator (written 3) door, push the red button to stop it. Look up to find the emergency lock that will allow you to open the elevator door.
Enter the third floor and walk up to the door to reveal the achievement.
