He did exactly that earlier in the game. What makes the Joubert decision worse, was that he wasn't sure. He can deny that now all he likes but the fact he stared at the big screen after he'd awarded the penalty and then sprinted off the field at the end suggests he knows he got it wrong.
It wasn't clear and obvious and the one thing World Rugby has been desperate to eradicate is marginal, controversial decisions.
Which brings into play the second issue. This tournament has seen the powers of the TMO extended to the point where barely a try has been awarded without their say-so. Foul play has also been scoured for and found pro-actively by TMOs.
It has meant for longer games. It has meant for periods - sometimes minutes at a time - of waiting for a TMO to trawl through endless replays to make their minds up.
It ha been excruciating at times but the pay-off, until now, was the accuracy of the decision-making. Everyone can handle waiting if it leads to the right decision.
So there are two question pertinent to the last five minutes of the last quarterfinal. The first is why didn't the TMO intervene when video footage showed Scotland fullback Stuart Hogg being late shoulder-charged by Drew Mitchell?
The incident may or may not have been that bad but why wasn't it reviewed? What if he's cited for it now - as he presumably will be - and found guilty of committing a yellow-card offence?
It won't change history but it will confirm that the officials failed despite having the resources there to ensure they don't fail.
The irksome part of that from a Scottish perspective is that Sean Maitland was yellow carded on the back of a TMO decision earlier - ruled to have deliberately knocked on. It was a harsh and hard to justify call.
The second question is why do the rules as they stand, prevent Joubert from asking the TMO to help with the ruling that led to the last minute penalty?
Why allow technology to intrude as far as it has but not then provide some kind of mechanism for it to be utilised at such a crucial period?
We have to wait an age for TMO's to rule on most things. Why not just wait a little bit longer to give them jurisdiction to rule on all things?
Technology's role has been increased for one reason and one reason only and yet Scotland have been knocked out because a referee made a mistake.
If Australia had conjured some late magic as they did against Ireland in 1991 to save that game - then brilliant. But they didn't - they didn't earn.
