Gavin & The End Game Walkthrough Part 4
Walkthroughs For Blackwell Deception
Confronting Lisa & Freeing Rosa
Send Joey back up to Rosa and then switch to Rosa. Click on the door and Rosa will call out and be answered by Lisa. You can explore all the dialogue options you want, but the important one is Gavin is going to kill you.
It won't take long for Rosa to convince Lisa that she's not joking. Lisa will flee, leaving Rosa stuck on her own with Gavin. This next section will unlock the Steam Achievement Unbound, which is unlocked by freeing Rosa.
Switch to Joey. There is a glass on the shelf along the back wall of the room. Have Joey blow it off. Then have Joey use his Tie on Rosa.
You'll now be able to tell Joey where to pull Rosa. You need to move her right twice, then towards the back wall once. Now switch to Rosa and click on a piece of the broken glass. She can reach at least one of them.
Then have Rosa use the glass on herself to cut the ropes, and she will be free.