I started experiencing GPU panics on rMBP in the past week as well, I guess NVidia or related circuits have some issues. I switched it off using gfxcardstatus and now it's stable running on Intel HD only. Try to do the same - if it stops crashing, your discrete GPU might be damaged.
I had the same issue with my mid-2010 MBP. They actually had a recall, but I was late to it! I'm somewhat disappointed that this issue still persists in some later models. gfxcardstatus helped a little in my situation, but the problem got so bad that I literally could not used the computer. $3K down the drain :(
I noticed Chrome crashing whenever I was in the Chrome store too many time. The 'graphics error happened' message after the crash was another clue. So I turned off native graphics acceleration in Chrome's setting and it's not crashed since then.
