MacBook Pro Panic Reboots

I think you have a failing Discrete GPU chip. This is a 2011 15" MacBook Pro, and they are notorious for failing Discrete GPU chips. I own one myself.

I suggest you look at

gSwitch (macOS 10.12 or newer)

https://codyschrank.github.io/gSwitch

and disable your Discrete GPU and run on the integrated intel GPU. That is how I keep, my 2011 15" MacBook Pro in service.

Yikes.

Safe Boot, (holding Shift key down at startup), does the problem occur in Safe Mode? Could take 10 minutes.

Safe mode attempts to repair Disks & clears lots of caches & loads safe Drivers, & prevents loading of 3rd party extensions, so if Safe Mode works try again in regular boot.