If you poke around with what I've said on the site, you'll understand my sincerity when I say: I do not care if I live or die. I welcome death because it would be a relief from having to think so much. I wasn't afraid because I am crazy. I didn't have to be stressed because I was okay with whatever happened.
In patrick's case? He has a wife and I think a kid (could be wrong)? Not to mention a ton of people relying on him to deliver something in the way of a successful game because their entire infrastructure of life depends on him (the whole team - and the company supporting the team- needs a quarterback that can make passes, if he doesn't make pass they don't get paid, etc).
I don't care about america, I didn't then. I didn't care about the soldiers working around me, or whatever happened to them. To be completely honest, I emotionally and morally disengaged from the situation the moment I signed up. It's just a job, if I don't do it right - then I die. It's an "if __, then __" predication, not one that I really have a whole ton of control over.
Patrick Mahomes is, in-essence, in control of the situation. That's real stress.
Now let's put me and him in context, since you want to compare the levels of stress.
When I deployed (4 year contract, single deployment), I was an E-2 and was promoted to E-3 while there (later E-4 upon returning home). I was a footsoldier. There were soldiers in my company (120 ish dudes) who didn't know my name. One guy in my platoon that refused to learn it "you don't deserve to have a name." I'm also the younger of two middle children and a high school dropout. My family really couldn't care less what happens to me.
Patrick Mahomes is a household name. If he isn't there, he's getting close. Not on Tony Hawk or Michael Jordan level, but maybe one day? Everyone is going to know if he screws up. He will not be able to hide from it. Imagine a "buffalo bills kicker" - esque situation from their SB run in the 90's. You are at the peak of social fame and acceptance - he's a less-political and better-at-football colin kaepernick - and he could drop to the absolute rock bottom at any second.
I don't want to imagine that level of stress. I intentionally de-stress my life by doing a whole hell of a lot of keeping myself grounded through negative self talk. I believe he got close to 2400 cal in 4 hours, doesn't surprise me one bit.