I must admit I didn't really get why Spock shouted Khaaaaaaaan other than to be homage TWOK. I really cringed in the cinema when that happened. In the context of the film it made absolutely no sense for him to lose control like that even if the person dying is Jim Kirk. Their friendship wasn't even properly established by that point. I hope we don't see too may outbursts of emotions unless he's due a Pon Farr.