Well so far we have no eyewitness accounts cause the Mallers did not have any journals and Scratch has not had her time to tell her story yet.
They were attacked on the way to the arena as mentioned and must have been attacked at the mall or they would not have drove the tankers to the Arena to blow them all up..
I do not see the Mallers putting that much effort into it if they had been left alone. Plus I recall in Kalani's story they were beefing up the mall when he got there to keep the Zombies out.