...and things like surgery and accounting and defending aren't stressful? I'd argue those can be and are more stressful in general because you have a life our your livelihood at risk
I'd argue that you're more at risk when everybody's armed. At least if somebody goes crazy, he has to go home, get his gun, and come back. Hopefully by then, he's calmed down. But if he's already armed, there might be a "spur of the moment" tragedy.
I don't think people should be allowed to carry concealed weapons anywhere for that reason (among others).
And incidentally, if it took professional police/sharp shooters 2 hours to bring him down, do you really think untrained (or less-trained) civilians would have had more luck? There's a good chance that they'd injure somebody else or get themselves killed if they'd tried.