Grab Gary's coat from the floor after the cutscene. Return it to him then place your rose inside the vase. Save your game afterwards then head out the door.
Head down the stairs and into the next area. In the next area take a left turn and you'll see a display area with 3 mannequins and an entrance.
Enter throught the entry way and it will close up behind you. Make your way to the bookshelf on the opposite end, but be careful of the roaming mannequin.
After reading the book you'll find out that it says nothing about how to get out of here.
Proceed to the paintings on the northern side of the area and examine the middle one. Press the button and a path will open. Head out through the path to escape from the mannequins.
Head further left and then up the hallway. Continue walking until you reach the hallway on the northern area then proceed to the right.
Save your game and proceed further right and enter through the southern door in the next area.
Inside the room there's a mannequin and a cord. Gary will automatically move the mannequin as soon as you get inside the room. After he moves the mannequin, examine the cord on the right side and pull on it.
Head outside the door that the mannequin was blocking and you'll see that the room connects the northern and southern hallways. You'll also notice that there's some text on the right side of the wall now. Examine the wall and Gary will start talking.
After a while of dialogue Gary will ask you the first world of the floor painting that you used to enter the Shadow Gallery. The answer is "Abyss."
Head back through the the room that connects the two hallways and out the northern hallway. Examine the door and Gary will say that the password is supposed to go here. After that the door will open.
Feel free to examine the books but our main goal here is the painting in the middle of the room. There's going to be a short cutscene after you examine it.
After the cutscene head back outside the room and proceed to the right side of the hallway. Save your game and follow the red footprints towards the only door on the right side of this area.
You'll meet a third character after you enter through the door. Go along with the dialogue then proceed to the right side of the hallway and up towards the next room afterwards.
The next area is just a filler so proceed right then up the stairs into the next area.
In the next area, take the path on the left side of the hallway and enter it. You can ignore the save point for now.
Inside the room there are a lot of cuddly bunnies. Examine the portrait in the middle of the room and there'll be a small dialogue. After that proceed to the bookshelf on the right side and a bunny will drop.
Grab the key from inside the rabbit and head out the door.
Once you pass through the middle section of the room the painting will come to life and cut Gary off from Ib and Mary. After the short dialogue, you'll be left with controlling Ib and Mary while Gary stays behind.
Save your game and head inside the room on the right side.
Inside the room start examining all the open boxes in the area. After you've examined all of them the lights will turn off.
After the lights come back you'll notice that the way back to Gary has been blocked by the statue and the only way out is through the other door. Use it to get to the next area.
In the next area just follow the path through to the upper part of the map and enter the door.
Save your game and step on the blue portal looking thingy on the ground to regain control of Gary.