Video shows a large crime scene in the parking lot around 1 a.m. Sunday.
Police say the two people who were hurt were already at the hospital by the time officers arrived at the scene.
Both of the victims are expected to recover, police said.
Although police don't know what exactly led up to the shooting, initial reports indicate that a group of people got into a verbal altercation in the parking lot when someone opened fire.
The Mainland City Centre is the former Mall of the Mainland, located at 10000 Emmett F. Lowry Expressway.
No arrests have been made, and police did not have a description of the suspect(s) in the case.