the 1600 is a special sort of torture. You don't remember how bad it is until after you're foolish enough to line up for another one. Then when you get to 500 or 600 meters, you realize you're in for it. But too late to escape, except by a humiliating drop out.
When you pass 800 meters, everything goes into slow motion. The 3rd lap is eternal. And hell arranges to have two or three people pass you, and quickly gap you by 20 or 30 meters. To finish the 3rd lap, first you have to complete half of it, then half of the remaining 200m, and half of the remaining 100m, and so forth ad infinitum - it is mathematically impossible to complete the 3rd lap, literally takes forever. I think many runners disappear into an eternal 3rd lap time dungeon.
If you do somehow manage to complete the 3rd lap, by then you are in a state of pure agony. But it is physically and mentally impossible to drop out of a race with less than 1 lap left. So you have no choice but to endure another however many seconds of existential dissolution.
When it is all over and you have recovered, your mind blocks out the horror from memory. You could not live a normal life otherwise, you'd go insane. Unfortunately this leads you to run the mile again and again, until your soul is severely scarred and you are doomed to a life of subtle dementia.