Also, I think that was about as lucky as you can get with the guard room, vault door and back area civilian spawns.

Didn't know number 2. 1 I knew, but don't have the saw yet. 3 I know, but this was supposed to be a "quick stealth for XP bonus"

Well done. Just a couple of tips:

1) If you have the silent motor mod for the saw you actually can saw open all the deposit boxes in the vault without disturbing the tellers or the customers, provided you got that same vault door spawn. It's much quicker than lockpicking and I usually just take all the loot from the table and run if no one has a saw.

2) You can only take as many police/guard hostages as there are players who have the dominator skill. So if you're playing solo, you can have just the one guard hostage. Just shoot all the others that find you. They won't give up ever, unless the current guard hostage dies.

3) You obviously have a good grasp of the game mechanics, or at least the stealth part. Strongly consider upping the difficulty because the money and XP rewards rise considerably and make the game much less of a grind. The loud maps also get more fun as the number of special units rise.