I've probably seen that video a dozen times, each time makes me think a little bit. Especially since a lot of the trees I'm cutting(when not out on fires) are hazard firs like that...luckily, most of the ones I'm cutting were killed by fire and the decay is usually just in the tops and in the sapwood.
You guys already said it, but that's a pretty shallow face for that tree. If the kerf
is starting to close that early in the face, it should trigger some alarms in your head...but without actually being there, I can't really judge the faller on that one. I generally go with deeper faces on the firs I'm cutting at work, as my goal is to "saw lean" into them and not dislodge crap up top by pounding wedges. That being said, I'm lucky to be able to not work by myself, so I've always got a spotter with their attention solely at the top of the tree. Even if they think they see something pop loose, their job is to yell at me at the top of their lungs. I keep my head up the best I can, but there's only so much you can see when at the stump.