[Ria P]

My Syrian hamster always goes to the same corner of his free roaming room to strip the wallpaper and he does it with a lot of enthusiasm. He's usually a very laid back hamster who is not known for energetic outbursts.
I've put a large cardboard backed brown envelope in his stripping corner which he also gets his teeth into but he will still hop around, try to climb behind the envelope and push it out of the way to get to the wallpaper.

You could try and shove a piece of cardboard under the door that folds up on itself or simply sit in front of the door yourself to see what happens then.

One of my other hamsters pulls on things when out of her cage like the buttons or sleeves of my cardi or sparkly bits on my Tshirt, a blanket, the carpet, anything that's pullable and she'll have a go.

Never does it in her cage same as my wallpaper stripper never strips anything in his cage.

All normal hamster behaviour in my opinion but they have their preferences and variations just like humans.