You won't like it because, I will be repeating the walkthrough.
After you took the green key - Take the handcuffs back from the planks.
Exit to Clubs hall, enter left door #4.
You should now be - at Diamonds Hall.
Go through the Queen of Diamonds door at far end.
See that there are 2 exits.
Start selecting the correct exits.
Select the exit that has the shorter pedestal 7 times.
Take the orange key from the pedestal at the center of the room.
Exit through any doorway and see Helena behind 2 exits.
Again, select the correct exit to Helena.
Select the skinnier Helena and go there. Tell Helena to "Stay Still".
Do the selections until you have Helena in front of you.
Talk to Helena. She is a friend. She came here to warn Sam only and is not associated with Mephistopheles.
Now you have to go to Hearts Hall.
From Diamonds Hall, take the right door #4 to Clubs hallway. Enter right door #1 to be at Hearts Hall.
Go to door at far end. Use the 3 keys on the keyholes.
Enter through door. Look-click on Mephistopheles. Sam wants something to coerce him.
Go back outside. Go through right door #3 to be at Spades Hallway.
Go to gun cabinet at left. Take the gun.
Go back to Mephistopheles. Go back through left door #3. Enter the Queen of Hearts door.
Use the gun on Mephistopheles.
Watch a great magician perform with possibly no props - the real thing.
See the RNG machine read IMPOSTOR.
The magician is the one in the picture. Note the tie clip.
Sam knows who is behind the incidents.