"She could have meant torturing us to the point of death and letting us recover so that she can repeat the process ten times," Trowa suggested.
"Or she could have meant actually killing us, and using blood transfusions with defibrillation to revive us." He frowned, peering at the... tattoo? Burn, maybe, although none of his burns had ever been blue.
Why mark them with 'ten', anyway? Why not simply mark them with a 'one', and continue the pattern on different body parts until they got ten ones on various parts of their bodies? And why start the process before she'd actually killed them?