According to the front page, if no one picks up the healing orb it automatically heals someone nearby for ~80%.
"Gift of the Serpent now creates Spheres that last 3 min, up from 10 sec. Healing amount doubled. If the sphere expires without being used, a nearby injured ally will be healed for 15,972."
I think this change will drastically put mastery ahead for either 10 or 25.