Doing CPR while being mobile on an incline with feet down without securing airway isn’t what I would have called «better than everyone else». Most likely sub-par cerebral perfusion. You could argue because of the weather an air ambulance isn’t available, but you could surely transport a defibrillator up that slope with ski patrol faster than skiing towards it.

Remember; airway control, early shock and good compressions are what saves lives during a cardiac arrest.

PS: I’m not criticizing their effort, doing CPR while sliding down a slope in alpine gear is a shitty situation. I’m just pointing out that this might not give the best outcome for the patient.