.. Visit the Old Flat

Tina: There are four floors, five apartments per floor. Ask around. ( Use the intercoms. You can skip the doors without intercoms. )

The exact location is randomized. You just have to try to find it.

Look for an apartment with the old lady. She will answer "Who's there?"

The correct dialog to get in: ( Tina: 2-2 )

Tina: Talk to Hilde about Tina's father. She will give you a signal disturber. You have to find the name of Ren's workmate.

Tina: Tell it to Hilde.

Go visit Smirk's Bar.