If you've got water and shade, someone knows where you are, you don't have any underlying health problems, and you're not exerting yourself, then any dry heat on earth is survivable. The saddest thing about cases like the Germans in Death Valley is how most of the mistakes were made before they even entered the park, and how easily they could have been fixed.

You did read the bit where they believed they were on an official trail, right?

I've spent two weeks combined solo off trail just wandering Death Valley, and will say I could have gone much longer. There's a lot more water back there than people realize, and parts of the year are colder than they are hot. HOWEVER, as a close friend of a friend of the superintendent and someone privy to SAR details, I'm telling ya, even on trail (on road) it's just not a safe place for most people once it's over 95° or so. Forget 110°! Many people suck at decision-making, and even more so once warm and suffering electrolyte imbalances. The Germans were some of _many_ to perish in Deva.