Perspective is actually correct. That is 3-Point Perspective followed exactly, it looks odd which is why most people don't use it.>>105171333
The fundamentals are actually on-point, and the feet situation is as well, it just looks very strange because that's not how people regularly see the world.
Alex Ross hires a model, takes a camera and positions the model in the exact pose that he wants to shoot, usually they are nude or in light underwear, and he then paints from there. The Figure is likely suspended by a harness, and flexing so because they are above air, their ankles point downwards as there is no ground below them causing the feet to look how they do.