they're going so fast that time basically stands still for them.

superman can get changed and exit a building in like 0.01 seconds (for tv adaptation its like a single frame or 0.04 seconds at 24 fps, still basically the same outcome) if the exit is like 300ft away, that's 30,000ft/sec. it's equivalent to compressing 30,000 feet of air in the cross section of a human down to almost nothing in a single second. most of this immense amount of air has no time to escape and becomes incredibly hot, thus resulting in superheated gas, i.e. plasma. a menacing superheated ball of death followed by immense shockwaves casually leaving the daily planet

yet all we see is a few papers fly off of jimmys desk or something