When you know how to wound or heal anyone.
(Heroes in room) Health Regen +16/+33/+50
(Heroes on floor) Health Regen +7/+12/+18
Paramedic is not a direct heal and can't replace healing through food. It does give a significant boost to health regen though, so it can allow heroes to heal up in small breaks between waves. The 'in room' and 'in floor' attributes stack concurrently in the same room. On Infirmary Pod mode, unlike other skills and items with health regen that become defense bonuses, this remains a heal making it invaluable.