R3 Misses Plate on Walk

[chuckfan1]

Im having a hard time on this one, that actually happenned, what say ye all?
Bases Loaded. Ball 4 to batter. R3 comes in, but misses home plate by about two feet, fair territory, continuing on towards his 1st base dugout. Starts high-fiving teammates, etc. Does not get all the way to the dugout.
Def coach notices this, and calls for the pitcher to throw the ball back to the catcher. Pitcher was standing in front of the mound. F1 throws to F2, who now steps on the plate, just ahead of the now conscious R3. R3 only tried to return to touch home, when alerted to the fact he missed home.
I ring up an out, out of instinct. Having never seen the play before, or probably never again, it just looked like an out.
Off coach argues that F2 needed to tag R3, and that R3 had up until he entered the dugout to touch home. Off coach asked me to check with my partner which I did. My partner stated that R3 was entitled to home, he was not awarded it.
He agreed with my call, and the call stood.
After the game, we talked about it some more, and I was having second thoughts. My partner stated how far do you want to protect the offense? The fact R3 blew right by home, didnt realize it, then only tried to retouch after becoming aware because of the actions of the defense.
Plus, he said you could get the out too, as he was high-fivin' when he returned to try to touch, getting a little push in the back, by the on-deck batter, to get back to home....."I'm giving this one to the defense."...he says.
I could be over analyzing this, but the fact that it was a walk, is what is sticking with me. Im having trouble getting past that. That it was on a walk. That I needed to give more leeway to R3 to touch, even though it was a stupid play, not necessarily a rules violation.
I have since got an AO on this, but first, has anyone got anything different? Or if the same call, but for a different reason? Thanks......