I read about that "plot hole" which I don't even consider a plot hole. Still the best action movie ever made, and essential viewing around Christmas time!
P.S. Alan Rickman as Hans Gruber (man, I love that name!) is simply the greatest screen villain of all time. I'm a huge fan of the Bond villains but I can't even pick one that can match Hans Gruber. Maybe Christopher Walken's Max Zorin? But I'd still give Rickman the edge.