I'm a little confused. Other than obtaining it through a drop, there's a quest called "Another Way to Break The Seal" in which you need 5 sealed core with mysterious power. Now I keep getting different feedback when I ask people about this and I even looked through the forums about doing 50 runs so I wanted a little clarification.

Do I need to do 50 runs (if i never get the drop) or do I just need to do 5 runs for the quest?