She touched him lightly on the head with a rope, which was accepted practice at the pool.
The man's lawyer Sonya Vidal said Tume had been offended after the lifeguard hit him lightly on the head with a rope to gain his attention, because her actions were culturally offensive to Māori.
Vidal said Tume had been racially abused in the past.
Tume got out of the pool and raised his right arm as though to hit her, then grabbed the lifeguard and tackled her to the ground. He dragged her into the pool and submerged her underwater, the summary said.