Maybe some people should look at the pictures more closely or get their information from more reliable media. Actually the side of the plane got a hole, not exactly in a place where you'd expect any hole, and for sure not a door.
Investigation is pointing out that an oxygen bottle located in that area is now missing and could be the cause of the incident.
First thing to do before setting fingers to keyboard: check the facts.
Looking at the pictures show that it wasn't a door, but a part of the fuselage. Second, investigators eliminated bombs and explosives within hours, due to lack of burn damage and no traces of explosives residue. There is a missing oxygen bottle, and it is suspected that it caused the blowout. All known facts, and known before this article was posted.