The ticket you found is to a locker at Lexington Station, but it's packed with people and you have trouble in large crowds since the incident at the mall. You'll need to make your way to the lockers and find the right one without cracking up. You'll immediately seize up at the thought of crossing the busy station, so follow the instructions to maintain control. When you make it a few steps in, you'll have a complete meltdown and go into a little mini-blackout. Here time will appear to be frozen and you'll see your dead son Jason wandering around with his red balloon. You need to wander around for a set amount of time before coming out of your fugue. During this time, anyone you bump into will crumple to the ground like a marionette with its strings cut. Any time you catch up to Jason, he fades away and reappears somewhere else. Eventually you'll come to across the station at the lockers.
Head through the rails and then through the metal detector into the locker area. When you get inside you'll pull out the ticket and you can refer back to it at any time by pressing . You're looking for locker number three in group 18, which is in the opposite corner from where you come in. If you look at the tops of the lockers while walking down the aisles, you should see little plaques with the group numbers on them. The lockers themselves have their numbers on the outside and they are in two rows, one above the other. As you walk by lockers, you'll see instructions pop up on some of them, letting you try to enter the code. Your locker is on the far end of the aisle along the wall parallel to the one you start on, in the upper row of lockers.