Speaking as someone who was born and raised in Joplin, and retired to it in time for the tornado to trash my apartment that was right at the edge of the zone of total destruction (http://www.ancell-ent.com/1715_Rex_Ave_127B_Joplin/images/):

What made this particular tornado devastating was the fact that it hit Joplin's major hospital which serviced the region, and took that hospital offline.

We lucked out, in that by then St. Johns wasn't even the city's biggest major hospital, although the Freeman complex was a frighteningly few number of blocks away from it, we could have lost both and probably suffered twice as many deaths. At St. John a visitor and 5 people on ventilators died, but the hospital was otherwise successfully evacuated in an hour and a half as random people with those eeeevil large vehicles we in flyover country are castigated for owning just showed up and moved most of them. Over a several day period the local ambulance service transported over 1,000 people, a number to much more distant hospitals since I'm sure Freeman's ICU was way too small.

We plan for these sorts of things, and had enough spare hospital capacity, including smaller ones in the county and e.g. the beds for the nursing school at the local college were deliberately fully functional so they could help. The St. John's healthcare workers took their supplies and set up at our big multipurpose Memorial Hall,
and per these http://www.aocoohns.org/wp-content/uploads/2012/04/Walker.pd... excellent overview slides (WARNING, some really ugly pictures in the latter part of that, you might want to stop at the first CAT scan) a lot of "triage centers spontaneously developed at schools and intersections along the damage path" (we're the sort of people who march to the sound of cannons). Here's some pictures of those including I'm sure Memorial Hall: https://www.google.com/search?q=joplin+tornado+triage+center...

The critical cases from St. John's and the tornado went to Freeman, which was a zoo; per the above overview, there were more than 200 patients in a 41 bed ER running on emergency generators. This first hand account by the Stormdoctor (a storm chasing internist) is excellent: http://stormdoctor.blogspot.com/2011/06/first-response-mode-... (and no pictures, but some ugly trauma described, a hopeless case triaged with morphine, etc.).

WRT to [3], security footage from our brand new middle school, a sobering thing to realize is that we have it because the tornado barely touched the building and I'm sure didn't damage the recording equipment inside. The school was near the edge of the zone of total destruction, like my apartment complex, and probably got hit by spinnoff vortexes or whatever.

The edge was very capricious, note from page 35 of the NIST report [0] the severe damage to the bottom, south part of the Wal-Mart. My part of the apartment complex was immediately to the west, along the tornado's line of travel, and all that happened was that the "clubhouse"/office etc. got destroyed, and every top, 3rd story apartment got breached as well a few 2nd story ones on the east ... and no one in any of these, including the Wal-Mart, died.... But there were people inside running for the more secure back inventory section as the roof peeled off overhead, per an eye-witness report from a cashier I talked to later.

Back to the middle school: there was no serious damage visible on its north (nearest the tornado path) and west (the direction the tornado was going) facades. Officially 65% or more intact, we could have just repaired it, but that's another story about how the long term aftermath of such events can be a stage for megalomaniacal narcissists and carpetbagging sociopaths.

In the zone of total destruction there was very little other than piles of rubble....

Anyway, thanks for your attention to all this and the link to the NIST report, I'll look at it more closely to see if I can figure out the edge effects in my location. Which a ... NWS team, as I recall, that I ran into estimated the winds there were only 120 MPH based on e.g. how the bolts of the cell towers were sheared off.