How would you respond to this coach?

[Andy]

Here is a play I had this just completed HS season.

NF rules, R1 on second, one out, I am PU.

Batter hits line drive to F4, ball caught for second out, F4 throws to F6 covering second for the live ball appeal on R1. Bad throw, ball goes into dead ball territory. R1 was already diving back into second at the time of the throw, so she legally tags up after the caught fly ball. I award home on the ball going into DB territory. As the runner is proceeding home, the defensive team coach from the 3B dugout behind me asks politely,

"Can you explain that award to me?"
"Sure coach, as soon as the runner is done."

I explained the award - two bases from the time of the throw - coach was fine.

Here is my "what if" and question:

Assume R1 neglected to tag up and simply proceeded to home.
I explain award to coach, then coach says, "that's fine, but she did not tag up at second!"

How do you respond?