Find the dog whistle
Go to the Eastern save room then take the leader up. Go to the last door on the east then on your west there will be a room that has the dog whistle (the room that has two different entrance doors on the map).
Go outside the mansion – 2F
Go to the western save room. Climb the ladder up then move around the ladder to head south then go to the first door you find. This door will take you outside to the place where you should blow the whistle.
Use the dog whistle
Use the dog whistle in the corridor you arrived to. A few dogs will show up. Make sure you kill them to get the item you are looking for.
Collect the dog collar
Once you kill the dogs, you will find a shiny item on the ground. This item is the dog collar. Grab it. (See Mo disk locations – Resident Evil Remastered)
Examine the dog collar
Examine the dog collar and you will find a switch. Click it to reveal a useless coin. Examine the coin again until it turns into a key. You will need that key in the next steps.
Head to the 3rd floor
Head to the northwest of the second floor until you reach the ladder that can take you to the third floor (The place where there is a death trap). (See What is the Residence Door Code in Resident Evil Remastered?)
Collect the Armour key
Collect the Armour key from the floor of the corridor on the third floor. Once you collect the key, the trap will set in and the statue will start moving.
Replace the key with the useless one
As soon as the trap starts moving, replace the Armour key with the key you got from the dog collar. This will stop the movement of the trap and allow you to get out with your Armour key.