Its a door and as such it could obviously open. However it is VERY unlikely and even if it did open the depresserisation of the cabin would happen so quickly that no one would be sucked out (they tested this on Mythbusters).

At 35,000 feet, the force of the pressure makes a door nearly impossible to open. Even if someone managed to pull on it from inside, the pressure is so strong that you would have to be a blood relative of the incredible hulk to even make it budge a little. Doors for the cargo hold are the same way. Contrary to what some people believe, the cargo holds are pressurized and heated just like the cabin. If for some reason a hatch blew out, pressure would be lost in the cargo hold only and not in the cabin. This would warrant an emergency landing, since it probably indicates a more serious problem. However, the people would be unaware of it. Although anyone travelling with a pet checked into luggage might be rather unhappy to see the unavoidable outcome. I also emphasize that loss of pressure in the cabin does not suck people out of massive holes in the airplane. The seal on the door of many smaller planes can fail, but the door doesn't fly off, nor does it open. This occurrence is a next to impossible. I will conclude that the effects of losing the pressure at 35,000 feet in the cabin is still surviveable. The yellow masks would fall from the ceiling and yes, everyone would have about 10-15 seconds to get them on. The pilots would then make an emergency decent to somewhere between 5000 - 10000 feet, where the masks would no longer be needed. Flight would continue to the nearest suitable airport, and a landing would be made.

Not gonna happen in a pressurized cabin. Those doors, if you've noticed, open inwards. Besides the latches,cabin pressure keeps them shut. To actually open the door would require physically releasing the door mechanism and an equal air pressure between interior cabin and outside air.If that is indeed the case, then the cabin has already de pressurized. Getting sucked out, won't be happening.