I was deep in the drought-dried desert, in a remote valley surrounded by miles and miles of wilderness...the closest buildings or structures with lights were very distant and thoroughly blocked by massive mountain ranges in every direction. But...

The evening before I had been reading and keying out plants for some hours into the night...in my well-lit and windowed camper van. It must have been a lone and very conspicuous beacon out the in the middle of that vast darkness. The next morning I found the little Corixid wriggling in the sand near the van after I tossed some leftover water from a pan. I think you solved the mystery :-)

[Though it's been a very dry year overall in the region, parts of Death Valley did get some rain in September...I guess enough to sustain a small surface puddle somewhere not too distant from the apparently parched environs of the Eureka Valley Dunes.]