Sawbones (Fallout 3)

Sawbones is a Mr. Gutsy working as a doctor in The Citadel. He can be found in the B-Ring and offers the same services that all the other wasteland doctors offer.

When you first interact with him, you can ask to be healed, in which he malfunctions and ends up hurting your player character. After the mishap, a new dialogue option opens up and (if your PC has a high enough Science skill) you can repair his malfunction through dialogue choices to receive some free healing.