Make a save here, because you have two options: throw it in his face, or put it in the trash. Past this, you'll find a soldier toss a can on the ground, and he'll tell you to put it in the trash. Use your interact button (defaulted to ) to open the door and hit a loading point. When an actual soldier knocks on the door, enter the next room, climb a ladder, and stack some boxes so you can crawl out the window. Kleiner to inform him that he's found you. Barney will reveal himself to you from behind the mask and will call Dr. Leave it and walk past a turnstile and continue to a security checkpoint, then follow a combine soldier to an interrogation room. When you start the game, a mysterious fellow nicknamed the G-Man will talk to you, and when he's done, you'll awaken in a train car.
The Orange Box (X360): Half-Life 2 | Misc Achievements Chapter 01: Point Insertion