Apologies for the delay in posting.
Also, I took the liberty of adding a link in point 6 for understandability.
As multiple-vehicle MVAs go, that wasn't much of one.
1) Don't use your cell-phone while driving. Accident stats for hand-held cell use make it look like the equivalent of drunk driving.
2) That wasn't much of an MVA. The vehicles were widely spaced; there wasn't much body damage (one with a crumpled hood, nothing else). There was quite a lot of smoke, but it was the wrong color. Gasoline fires have black smoke. There seems to be quite a bit of sparking, much like what you see on the bridge in Star Trek when the engines canna take any more. What exactly is causing that I don't know. I'm not aware of anything on an ordinary car or truck that'll do that. If any vehicles are on fire, stay well clear and keep others well clear.
3) Stop your car as safely as you can. Turn on your four-way flashers. Grab your bag and boogie off the road, 45 degrees, heading upstream toward the flow of traffic, so the guy who slams into your car doesn't send debris into you.
4) Call it in to 9-1-1. Take the flares from your go-bag and flare out the scene. One flare at 100 feet (20 double paces), one at 200 feet, one at three hundred feet.
5) A police officer is on scene (or, at least, a cop car with its lights going is on scene). Find the officer; report in and ask for an assignment.
6) Go into a triage mode. I've discussed this in some detail elsewhere.
7) I note that the young lady first comes to a guy with a head injury who is guarding his left arm. That generally means he has some kind of arm injury. She grabs him by that arm. This is contraindicated.
8) There don't seem to be any serious injuries. Stay safe yourself.
More interesting posts about medical and emergency issues by Jim Macdonald can be found here at Making Light.