They have keys.
Silly of me to overlook that. But, they might also have a deadbolt for extra security when someone is trying go get in. I don't know--maybe someone else can chime in on that.
Also, I note the article says the plane was at 7000 feet, which means the call was probably made after the excursion to 43000 feet, which may have largely disabled anyone on the passenger side of the door.
Keys won't help if there is a dead bolt lock inside the cabin. I heard it stated that some 777s have that feature.-Tom
Do they? Or is it policy to leave the keys in the cabin with the thought that a passenger is more likely to be a hijacker rather than the other pilot? And is that really done even if it is policy? I could understand the airlines being silent about that.