Festival City parking lot battery died right after grocery shopping

Nothing like finishing a big shopping trip at Festival City, loading up the trunk, and then your car just clicks at you. I was parked on the lower level near the water front and of course I didn't have my jump cables because I took them out last month and forgot to put them back. A security guy tried to help with a portable pack but it was dead too. I started calling around and most mobile services said they'd take 45 minutes just to get through the mall traffic. Someone in the queue at the parking payment machine mentioned that there's an Expert Battery Installation in Festival City  that operates specifically around that area and knows how to navigate the congestion. Has anyone actually used them for a mall parking rescue? I'm mostly worried about the cost because I feel like they'll overcharge since you're stranded and desperate. Also curious if they can install in a cramped parking spot without enough room to open the hood fully because there was a pillar really close on the driver's side. Just trying to get home before the ice cream melts.