This memorial is to the chivalry displayed during the fighting. An Australian officer was wounded and moaning in no man's land when an Ottoman sergeant waved a small white flag and hopped out, scooping up the wounded man and running him into the Australian trenches, then running back to his own lines. This is not legend but well-documented. "Mehmetçik" is a casual term for Turkish soldier (like "doughboy" for a WW I US soldier, or "Tommy" for a UK soldier).