Dunedin Senior Sergeant Craig Dinnissen said the boy had frightened his friends with the cap gun on Monday before heading to the mall in the late afternoon.
He allegedly presented the cap gun when he was inside the mall about 10 metres from the entrance and pulled the trigger of the cap gun twice.
The following day he returned to the mall while intoxicated and allegedly threatened to stab a security guard.
He was arrested on Wednesday.
Snr Sgt Dinnissen said there could have been far more severe consequences for the boy, potentially with the armed offenders squad being called.
His stunt with the cap gun "should not be contemplated", Snr Sgt Dinnissen said.
He was charged with breaching bail, possessing an imitation firearm, and threatening to kill.