Current event system has Disable revival and Prevent player damage options.
If Disable revival is enabled, whenever player reaches 1HP, he dies immediately without laying on the ground (downed state)
If Prevent player damage is enabled but Disable revival is disabled, whenever player reaches 1 HP, he can't be killed by other player's direct attacks (punching, shooting).
Dani indeed warned other players not to punch others during the event. That implies that he was allowed to take any action towards participants who didn't follow event rules, including slaying them.
On the other hand, event host, Zack, didn't enable Disable revival option neither disable Prevent player damage option which wouldn't even lead to this situation in the first place.
I believe Dani's actions were justified, however event planning could have been better, settings-wise.
DISMISSED.