50 degrees, Body Armour, small glass cockpit, no aircon? Welcome to the world of AH/SH pilots who've been operating in the thick of the threat band at low level in tightly regulated airspace in Iraq / Afg since 02. I did plenty of 8-9 hour tasking days in Iraq with ambient temperatures of 45+ (and cockpit temperatures well above 50), with no facility for keeping cold fluids on board and often with no opportunity for unstrapping. How did we cope? We lived in tents (no aircon) and acclimatised properly; yes it was uncomfortable but we were fully aware that our "suffering" was substantially less than that of our customers.
8 hours at 10k plus with a few cold drinks? (Relatively) easy money...
At 10k plus with low visual/acoustic signature the ac will be hard to acquire visually for a MANPAD shot, then, I'd imagine, quite hard to lock as it'll have low airframe heating (plastic and low speed) and low engine exhaust signatures.