First: the runner was safe, tag or no tag. Bracket that, it's not Johnny's question.
The way the NCAA rule is written is potentially misleading.
What it says literally is that voluntary release is sufficient for complete control (and thus a tag).
What some coordinators seem to read it as saying is that voluntary release is necessary for complete control.
That's always bothered me. As I don't work NCAA, I haven't had to deal with it. I feel better now.
For this play, I have the fielder losing the ball as he stands up. I do not see him "regaining body control," as he is in control on a knee as he makes the tag, and he could have remained there holding that sno-cone indefinitely. It's definitely a second act of standing up that causes the ball to come loose.
So, as I read the rule (voluntary release is sufficient proof of control but not necessary), this is a [late] tag. The delay between tag and standing up is sufficient proof of control.
Compare an outfielder who makes a sno-cone catch for the third out, regains his feet, runs to the infield, and 5 full seconds after the catch the ball comes out (involuntarily, and probably nobody notices). We're not ruling a catch there because the release is not voluntary?