It appears as if many climbers were lucky to be not hit by the avalanche that wiped out camp 3 on K2. Serge Dessureault has written on Facebook what actually happened and why some of them were lucky to be alive.
He said that the day before the avalanche about 12 Sherpas went up to camp 3 so as to start preparing for the other climbers from their expeditions. However, at some time that day they decided to exit back to camp 2 so that they could talk tactics with the other climbers. That night the avalanche happened and all of camp 3 was wiped out. No doubt everyone in camp 3 would have perished had they still been there.
Also he mentions what would have happened had this avalanche occurred 24 hours later. Many more climbers would have come up from camp 2 to stay at camp 3.