Are you suggesting that the roast is too soft? Or too hard?
5" of roast is as good an approximation of flesh as is ballistic gelatin or a 1/2" pine board. I'd wager that if a .22LR at 300 yards could go through that roast, and it did, then it would probably go through your arm, or your calf or perhaps your thigh. It would certainly hit your pelvic bone after passing through your gluteus maximus. If it missed the ribs it could go through your heart and out your back.
I'm suggesting it isn't a suitable tissue simulation... Because it isn't. Living tissue is not the same as dead tissue. Animals can be used as a semi-close substitute in some cases, but only when it's a fresh kill. They specifically mention that the meat had gone bad. And it was partially frozen. Whether these conditions would make the round perform better or worse, I'm not certain. But it is certain that it is not a suitable simulation of performance in live tissue.
Further, the FBI recommends at least 12" of penetration in properly calibrated ballistic gelatin as the bare minimum for optimal terminal performance. So the 5" we got isn't even enough to give us a good idea of the true terminal performance and properly evaluate it. Nor did they actually measure the wound channels, giving us even less hard data. All we got was "It has holes in it and some of the rounds expanded!" Well, okay, that's great... But it doesn't help us quantify the performance. Which is rather important.
And no, it is not as "as good an approximation as ballistic gelatin." And I wouldn't consider a pine board to be a good measure of ballistic terminal performance either.
If you wish to make that wager, that is your call. I will simply say we do not have enough data to actually determine if any of those things would happen for sure or not.
Ya, I'd call that lethal. People have survived multiple wounds with higher calibers, and they have died from a single .22 shot to the chest. No handgun has "knock down" power. They all punch holes and cause bleeding. Punch enough of them and the target is in serious trouble. You just have to stay behind enough cover till the bleeding takes affect. Of course, you can always take a perp quickly out with a single shot to the brain or brain stem, regardless of caliber, if you are that good a shot.
No one (well, at least I'm not) is debating that. Most people who have any knowledge of terminal ballistics know that handgun calibers are poor performers compared to long gun cartridges. But even the best .22LR I've seen testing for under performs a great deal compared to 9x19mm or larger handgun calibers. I was debating the validity of this "lethality test," not saying .22lr can't be lethal. We have an incorrect testing medium combined with no actual measurements of the wound channel and not enough of the testing medium to determine how much penetration there actually was for the rounds that punched through. 5" of penetration is considered to be less than half of the recommended penetration depth for optimal wounding.
That is what I was trying to say, although I admit I did type my response quickly so you could only assume at my meaning.