Quick Flame Heart is a simple trick that helps Dante or Lucia to grab the Flame Heart as they fall on the ground. It maintains the movement momentum where it saves considerable amount of time.
How to perform
When you enter the hollow center of the tower, make sure that the character is at the centroid and facing right to the exit. Lucia's position is bit tricky cause of the Red Orb dispenser.
Do the highest Air Hike possible then fly-up. Count the number of times that you ascend, which should be 9 times.
The 9th time is where you time unDT and quick tap forward with d-pad at the same time.