Why does Hyesung survive in route B? Not so much that Do-yoon is the one who checks on him, but because Gyu-hyuk wasn't the one who checked on him. In other words, both A and B had him still lingering when found, but Gyu-hyuk had incentive to wait just long enough for him to finish dying (if not quicken the process by applying pressure to make him bleed out more) before reporting said demise. Or, even worse, dissuade anyone from helping Hyesung, thus keeping him bleeding for maybe another half hour or so...
