Participant should not have put as much trust into walking poles - they are clearly not a substitute for an axe, and using either crampons or an axe in this terrain would have almost certainly prevented the slide from being as far. As soon as there are any sections where you are unable to kick steps should be a sign you should use winter gear.

However, participant also didn't want to slow down their walking partner (both having similar experience, but partner being more physically fit, hence being further up the hillside). Both fell into specific heuristic traps: the participant of not wanting to annoy their partner by "being slow"; the partner of not offering the participant proper rests, by stopping to allow the participant to catch up but then immediately walking off again.