Well, the danger in doing that is roughly equal to the danger in driving a car - in case of an accident up to maybe a dozen people will die.
Space elevator collapsing would probably end up being a major disaster in more than a dozen countries.
Um no. A space elevator would be immensely heavy but that weight spread out over many hundreds of miles, most of it out where the atmosphere is very thin. So if you severed it, most of it would continue it's orbit for quite some time. Any collapse would have plenty of warning and would be very light damage over a wide area.
"if we had a space elevator" is about as useful of a statement as "if i had 10 billion bucks i'd totally stop world hunger"
factors sure do have a lot of potential... but that doesn't mean that they'll ever be manned
The moon doesn't make a good staging point... its a gravity well that you need to escape whenever you want to go anywhere. (though i guess with some kind of rail gun it can make things stack up better)
Considering that Unicef spends 2.5 billion dollars a year alone and there is hunger in nearly every nation in the world, stopping world hunger for even a year on 10 billion dollars would be an impressive feat.
And the moon makes a good staging point for two reasons.
A) No atmosphere to slow down your projectiles and limit your top speed
B) Much, much weaker gravity
Keep in mind that you don't need your initial launch to reach escape velocity of the moon. You just want to get up about 100-200 km and do a relatively slow burn to move out of lunar orbit.