Fellow binger (yes, treated for it, no not in a good place with it rn, I will get my head back together).
This is a huge volume of *food,* not just calories. 6500 calories in a few hours of binge is doable if you're binging on something with small volume but high calorie density. (It's about three and a half tubs of Ben and Jerrys.) But 3 feet of a party sub is just a fuckload of room in your stomach. Physically getting all that down and keeping it down over that period of time is so far beyond my personal capabilities that I'm head-tilting trying to figure out how it was done.
If OP can actually kill half a party sub in that time frame, it's time to start entering some competitive eating events, because his capacity is amazing.