Steep stands hurt on the way down, not on the way up

Descending a raked stairway loads the thigh in the lengthening direction, which is where control fails first.

Everybody assumes the climb is the hard part. The climb is the tiring part. The descent is the dangerous one, and the difference is which way the muscle is working.

Going up, the quadriceps shortens to straighten the knee and lift the body. That costs energy, it raises heart rate, and it is why people are breathing hard at the top. Going down, the same muscle has to lengthen under load, paying out slowly to lower the body onto the step below. Lengthening contractions produce more force for less oxygen, which is why the descent feels easy, and they also produce far more microscopic damage in the muscle, which is why your legs ache the next day after walking downhill rather than uphill.

Now make the stairs steep, because a raked bowl with good sightlines is by definition a steep bowl. The steeper the riser, the further the knee has to bend on each step and the greater the demand on the thigh at the exact moment it is least mechanically favoured. Add a crowd setting the pace, hands full, a phone, poor lighting between blocks, and a tread depth that is shorter than an adult foot.

The failure mode is not usually a muscle tear. It is a missed step. As the quadriceps tires, its ability to control the rate of knee bend degrades before its ability to generate peak force does, so the body drops onto the step slightly faster than intended. If the foot lands on an edge rather than a tread, the ankle rolls or the person pitches forward down a gradient with nothing between them and the next twenty rows.

This is why concession timing and stairway design are joint questions rather than separate ones. A layout that dumps three thousand people onto the same two vomitories at the same moment does not just create a queue. It sets the descent pace for a crowd that includes people whose legs are already done, and it does it in the two minutes when everyone is looking at a phone instead of their feet.

The engineering answer is boring and known: deeper treads, consistent risers, handrails within reach from the middle of a flight, and enough parallel routes that nobody descends at somebody else's speed. The reason it keeps losing is that every centimetre of tread depth is a seat somebody wanted to sell.