There'd been so much jewelry there. Somehow the geeks had known to hole up with it. Maybe they figured people would come after it, looking for some easy treasure, or maybe they'd thought to themselves that they could still strike it rich. All Vic knew was that those zombies were sitting on a fucking gold mine of jewelry and his wife was gonna kill him if she found out about it.
He and Josh managed to get out safely, settling onto their bikes just as the department store doors opened and some shufflers started to pick up the pace. Vic made eye contact with Josh, kicking his bike into gear and getting the engine running. He let it idle for a moment, though, backing up and giving Josh time to get his own bike going. Better that Vic was the first one the geeks found if they got close enough.
"No. Yes. She's gonna be pissed as hell. Come on!" Once Josh got going, Vic would follow. But in the meantime, if he needed to hold them off, just in case anything was wrong with Josh's bike, he could do that.