Standing atop the Hoover Dam, a massive concrete edifice rising a quarter of a mile above the Colorado River, I couldn’t help marvel at human ingenuity.

Below my feet, enough concrete to build a four-foot-wide sidewalk around the earth filled a narrow canyon. The smooth-walled human-made structure did not look out of place amid the rugged stone walls rising on both sides. The lake imbued the air with a stillness that permeated a timeless work of art. A bird rising from the abyss settled on the steel railing, keeping people away from the edge of the dam. It sat there, looked around, and disappeared back into the depths. A short while later, another bird came up, and the scene repeated itself over the next hour while I waited for the sky to declare it was sunset by bursting into a palette of red, orange, and yellow.

My mind kept drifting to this scene imprinted in my memory as I sat in the windowless call room of the hospital, waiting for the beeper to fall silent. My brain, numb from the constant electronic chirping, refused to allow my hands to pick up the beeper as it went off for perhaps the hundredth time that night. It was the morning alarm—time to sleep. The next shift was taking over. The vibrating block of plastic, flashing red and yellow lights, drifted to the edge of the side table and fell into the garbage can. It took the remnants of light in the room as fatigue forced my eyes shut.