Leadership, Volunteer, or HCE?

[kehsiao]

Hello. I am wondering what category this experience should fall into.

I was a pharmacy administrator officer for Flying Samaritans an organization that would go to Mexico to volunteer and provide healthcare. I led the pharmacy unit along with the rest of the medical unit to Ensenada and oversaw the flow in the pharmacy, ensuring that medications were efficiently and correctly dispensed. I would even dispense and provide special instructions to patients w/ pharmacist counsel. 

Would this fall under Leadership since it was an officer position, Volunteer since it was unpaid, or HCE since I worked in a healthcare setting? 
 

Any help or advice is greatly appreciated. Thank you!