Oh, now I see what you mean. I never did more with DCSS ASCII than try it out; I've always played tiles and used the mouse for long-distance movement.
Instant arrival is an interesting notion... TGGW has that as well. It wouldn't be too difficult to add, assuming a very robust system for stopping a run when necessary. I've added this to the medium-term list of things to look at, along with the expanded auto-stop feature.
And Escape should cancel a run, yep, as should Spacebar (which currently does, but also has the side-effect of showing your last UI message at the same time). Right now a lot of keys will stop a run, but they have side-effects as well since they still cause their normal result even though you were running. Not exactly consistent. I'd probably prefer to have players stick to ESC/Spacebar/r, which makes entering other commands in the middle of moving possible. We'll at least start with those.