"Agreed. Best way to think about this is as conjoint probability. Amy is saying something like: "Given terrorists have seized an aircraft and crashed it into a building, what is the risk the building will collapse?" In that event, the odds…"
"You've made two mistakes in your computation. I'll note one. If the risk of catastrophic collapse of 1 of 5000 buildings is 1 in1000, then the risk becomes 1 in 1 if you build 1M buildings, In other words, certainty, and, if…"