They are free to do anything to help support the community and grow the project. They receive early access to some parts of the project. The Medic bonus is a reward that the project gives to Medics & volunteers. It is not a guaranteed payment or compensation at this time, not until the CREE Bank (claim portal) opens. The amount given is automatically calculated monthly, based on an algorithm that includes (and not limited to) factors such as ETH market & prices, Twitter growth & activity, Discord community growth & activity, project sales, and the Medic’s performance and activity.