A bit personal, but having my ribcage opened with an electric saw, my heart stopped for a few hours, my lungs deflated, and a machine keeping me alive while about 6 people worked in various capacities around the operating table without inadvertently pulling any of the leads or tubes out (or maybe they did, how would I know?), one of them stitching harvested blood vessels onto my heart with teeny-tiny stitches still blows my mind.
If this is all a simulation, the level of minute detail in it is astounding.. Either way, modern medicine is a miracle.