I don't see any tension between these two remarks.
Here is John Harper on soft and hard moves in AW GMing:
I keep seeing some people struggle with this, so here's a handy guide to hard moves in Apocalypse World.
When you make a regular [=soft] MC move, all three:
1. It follows logically from the fiction.
2. It gives the player an opportunity to react.
3. It sets you up for a future harder move.
This means, say what happens but stop before the effect, then ask "What do you do?"
. . .
When you make a hard MC move, both:
1. It follows logically from the fiction.
2. It's irrevocable.
This means, say what happens, including the effect, then ask "What do you do?"
. . .
See how that works? The regular move sets up the hard move. The hard move follows through on the threat established by the regular move. . . . [A] hard move doesn't automatically equate to severe consequences. The severity of the threat is a separate issue, depending wholly on the fiction as established. The hard move means the consequences, large or small, take full effect now.
It's not about being mean, or punishing a missed roll, or inventing new trouble. It's about giving the fiction its full expression. Setup, follow-through. Action, consequences.
He gives some examples of soft vs hard:
He swings the chainsaw right at your head. What do you do? vs
The chainsaw bites into your face, spraying chunks of bloody flesh all over the room. 3-harm and make the harm move!
You sneak into the garage but there's Plover right there, about to notice you any second now. What do you do? vs
Plover sees you and starts yelling like mad. Intruder!
She stares at you coldly. 'Leave me alone,' she says. What do you do? vs
Don't come back here again.' She slams the door in your face and you hear the locks click home.
He also gives an example of what
not to do:
I've seen people struggle with hard moves in the moment. Like, when the dice miss, the MC stares at it like, "Crap! Now I have to invent something! Better make it dangerous and cool! Uh... some ninja... drop out of the ceiling... with poison knives! Grah!"
Don't do that. Instead, when it's time for a hard move, look back at the setup move(s) you made. What was threatened? What was about to happen, before the PC took action? Follow through on that. Bring the effects on screen. Bring the consequences to fruition.
Harper's idea of
bringing consequences to fruition, of
giving the fiction its full expression, is what I am getting at when I refer to consequences as being implicit in the fiction. If what the GM fails in that respect - if, to the players, it's like ninjas dropping unheralded from the ceiling - then you're probably into my "oops" territory.
Your famous gorge is (by the sound of it) not like that at all. The players are having their PCs attempt a cross-country escape relying on their riding skills and their familiarity with the countryside. A sudden obstacle like a gorge is absolutely implicit in that situation. (Contrast: finding your path blocked by a UFO that has just landed is not; wheres if the pursuit were in air/rafts in a Traveller game than the converse might well be true!)
My own take away from BW's equivocation between its "official" instructions and its designer's admitted practice is that when the rules were first written there was less familiarity with the sorts of techniques we're talking about here, and so it made sense to urge everyone to be express, in advance, about consequences; but that as the AW style (which I dont think AW invented, - you can see it eg in Prince Valiant 20+ years earlier and even hints of it in Classic Traveller 30+ years earlier - but which AW expresses probably more clearly than any other RPG rulebook) became more widely familiar, the need to advocate such strict scaffolding around play fell away.
I think we can easily relate this back to the OP. Among other things, it appears that there was some sort of mismatch between the players' and the GM's conceptions of what consequences were implilcit in the fiction. My view is that this is a largely inelminable risk of relying on secret GM notes rather than treating
what has been narrated as the core of the established fiction.