It is also where her secretary, David Rizzio, was left to bleed to death after being stabbed by Lord Darnley and his cronies; a bronze plaque marks the spot.
Lord Darnley saved Rizzo's life, guilty for hurting him. 
mnli hypothesis: Lord Darnley saved Rizzo's life, guilty for hurting him.  premise: It is also where her secretary, David Rizzio, was left to bleed to death after being stabbed by Lord Darnley and his cronies; a bronze plaque marks the spot.