If in aos Trek Spock gets his Pon Farr on the second five year mission and they have to go to New Vulcan cause T'Pring is still alive, so that means they're still betrothed and the kal-if-fee need to happen. So as in Amok Time, T'Pring calls the koon-ut-kal-if-fee and choses Kirk as her champion.
Just imagine how it'd crush Spock, thinking his captain has died a second time because of him. James, this golden man, his captain, has died once again and all because of Spock. If Kirk's first death pushed Spock to bloodlust and rage, what would his second death do?
But then, as in Amok Time, Kirk would not be dead, but just imagine, how much it would've crushed Spock if Kirk had truly died by his hand.
I think that's the moment Spock really realized how much Kirk meant to him. Realized that they were t'hy'la