Bees attack the face. Recently it has been scientifically proven that bees have memory for facial features. He was probably cruised by a few “guard bees” before the colony was alerted. If you see little black dots making passes around you it is prudent to take notice before they go back and tell their family with their body communication signals where you are precisely located. The climber was either very close to the hive or he was dealing with an aggressive strain of killer bees.