Solidity of the walls is definitely an issue. But if the walls are sufficiently solid (they were talking about concrete buildings), the velocities were orders

Solidity of the walls is definitely an issue. But if the walls are sufficiently solid (they were talking about concrete buildings), the velocities were orders of magnitudes lower just to the sides of the doors and windows, so hugging the adjacent wall or just under the window will keep you from being picked up and flung downwind, as well as having the shrapnel flying past you and not into you. Big difference. I saw one post from a medic in the Ukraine war. He said 80%+ of the injuries he treated were because people didn't get flat on the ground fast enough. He then demonstrated how to do it correctly. Most people, when trying to get on the ground will first kneel, then lie down. He demonstrated how to do it in one motion, either straight like an inverse push-up or burpee exercise, or with a twist. Flat in <1sec instead of ~2-3 seconds makes the difference between "whew" and metal embdded in your body. Same can be true here. That's also why I mentioned opening your mouth, since the shockwaves bouncing around can damage tissues if air can't escape, but if it can, it just goes by. Nothing is a guarantee, but taking measures increased your odds a lot, which was the point of the study. May we never need it.