The Medic feat (from Unearthed Arcana: Feats for Skills) has the following description:
During a short rest, you can clean and bind the wounds of up to six willing beasts and humanoids. Make a DC 15 Wisdom (Medicine) check for each creature. On a success, if a creature spends a Hit Die during this rest, that creature can forgo the roll and instead regain the maximum number of hit points the die can restore. A creature can do so only once per rest, regardless of how many Hit Dice it spends.
Can a creature benefit from this feat for multiple hit dice?
Example: I short rest, and someone with the Medic feat binds my wounds. I use 3 Hit Die of d10 (Fighter).
Do I recover 30 HP, or only 10+2d10?
Best Answer
You heal 10+2d10.
Part of your emphasis on the feat description: "...if a creature spends a Hit Die during this rest..." Singular.
Last sentence of the Medic feature:
RAW on using hit dice to heal after a short rest (emphasis mine):
(PHB Chapter 8, Page 186)
This means the dice are rolled one by one and you decide to continue or not after seeing the first roll.
Also note that the Medic feature is used instead of rolling the die.
Note: If you are unsure whether the Medic adds your CON modifier to healing like i am check this question.