This seems like one of the few instances where a pry-bar style knife would be useful in an office environment. All things being equal, it seems like it would be easier and safer to pry open the doors then to climb around on top. Still, I think its safe to say the best thing you could carry after a cell phone, would be a water bottle, a couple of gallon sized freezer bags and a book. And from the article ear plugs. He was apparently having bad experiences from the alarm bell ringing for hours on end.