Bolded part it's prabably right.
Werdum knew he was winning, so he probably opted for saving Vinny's arm.
True, but Werdum ended up losing...sooo.....I'd say break it. The guy can tap at any time, it's his choice not to.
Everyones an expert it seems
Not claiming to be an expert, that is like a day one level armbar, anyone with just a little bit of time in can tell you how to execute that armbar, now finishing a world class grappler, that's a different story.
If you watch Vinny's wrist he manages to keep his palm down (or mostly down) the whole time which helps a lot. He also keeps his body sideways rather than on his back so his shoulder off the floor so his shoulder is taking some of the pressure rather than his elbow. Still impressive but I can see why he didn't have to tap.
Exactly what I was saying about Werdum not controlling his body with his legs and allowing him to rotate his arm. Simmilar to GSP v Hardy, where it looked like it was in so deep and how could he escape, but in reality he was never in very serious danger of having his arm broken because of the angle he got his arm to. It hurt that's for damn sure, but it would have taken so much to actually break his arm that he was able to not tap.