I remember a lot of side chat to the old nuking the fridge Crystal Skull debate being around these big old style fridges having proper latches that could only be opened from the outside rather than being held shut magnetically.
In the film we see Arthur climb into one of these big old fridges and lock himself in. Question is - How did he get out again? Or even - Did he ever get out again?
Maybe everything after he climbs in there is simply his delusional mind shutting down as he slowly suffocates / suffers hypothermia...
It had a handle, but if you notice it also had the magnets at the corners of the door, that's what the black circles are on the fridge. In the 50's and before you would have had a true locking fridge where the handle actually operated a mechanical latch that pulled the door air tight against the refrigerator, but when they were transitioning to the magnets the earlier version with a handle type lever were not actually locking anything they were just a lever that helped pop the door open because the magnets made it difficult to just pull open the door without giving it a jerk. That looks a lot like the type of fridge my grandma had when I was growing up and the door didn't actually lock but if you tried to pry it open by just pulling on the door it was very hard to do because the magnets were very strong compared to what you get today. Look at the handle as just a fulcrum to give the person opening a little boost in opening the door... but if you were inside you could easily push against the door and open it.