How to open vault door at FLC(Fallout) plus other ramblings

[Ben Flieger]

I blew ole' Lorenzos head off, then disposed of his guards. However, I am
now unable to open the door and steal the money that must be inside. My
lockpick skill isn't that good, and
din-o-mite doesn't work(note to Tim: THIS SHOULD WORK!). Also, Lorenzo
apparently doesn't have the key to his own vault(note to Tim: Why doesn't
he?). Is there any other way to open that damned door!

Another annoyance/question
Spoilers:

Annoyance: When I kill the "Rough Guards" holding Brother Jonathan hostage
in Old Town, why doesn't he recognize if I am a member of the Brotherhood?
He should assume that I am some sort of rescue party, not just some
gun-totin' do-gooder.

Question: Why doesn't Talus offer me the power armor as a reward? He asks me
to chose from Rocket Launcher(ok), Laser Pistol(good) and Super Sledge(why
is this on the same list as the above two?). But damn it, I want that power
armor, and that tightass Mike won't give me a systolic motivator. Red-tape
as far as the eye can see. How can I make them gimme the armor, and if not,
is there another way of getting it?