Absolutely possible.
Now reporting at least 3 gunmen.
Gang initiation is to shoot up a mall?
Come on. That's silly. How many other malls have been shot up as part of a gang initiation?
Now, I'm not saying for certian that this is or isn't terror.
But look. Gangs aren't going to shoot up a mall as an initiation right.
A robbery gone bad? Possible. But doesn't sound like it.
A random shooting? I can't remember a case (outside of school shootings) where such people didn't operate alone.