I believe this is to do with accruing a large amount of mess (food and drink) in your apartment, and you do that be getting two items.
First of all, when you initially visit the diner look to your left and grab a small pack of tea from next to the sauces. Don't take too long to do this as the scene will shift.
Next, when you are in Halperin's car and she stops at the petrol station for the first time, she will get out and walk into the shop. You initially have to check under the sun visor on her side (it forces you to do this) but there is nothing there. Now check under the visor above where you are sat to find a pizza menu. Grab it. YOU MUST DO THIS BEFORE CHECKING THE GLOVE BOX.
Now when you return to your apartment properly (not the first dream sequence) there will be a drawer full of teabags and a stack of pizza boxes in the kitchen. This should unlock when you look at them.
At least this is when I got it - so any alternative theories, let me know.