Borderlands 2 Walkthrough Part 18 – Sanctuary Sidequests, Part 3: Medical Mystery

Medical Mystery (Three Horns - Valley)
Head over to Dr. Zed's once you have completed, “Do No Harm” to get this quest. He explains that his rival, Doc Mercy, is using some kind of weapon that inflicts harm without bullets. This is something worth investigating in very short order. Head out of Sanctuary and back into Three Horns – Divide. From there head ove to the Western side of the Divide. Either of those exits will take you to Three Horns – Valley where you can find Doc Mercy. Heading through the Northwestern exit will put you much closer to Doc Mercy's hideout then the Southwestern exit and makes a lot of the quest faster.

Get to the Northern marker and head inside. This leads you into Shock Fossil Canyon. Once inside the Canyon head for the Northwestern part of it. You will find it overrun with Nomands, Marauders and Psychos. Fight your way through them all toward the marker. At the marker, and be sure that you have wiped out his support, you will find Doc Mercy. He is attacking you with an E-tech Weapon. Shoot around his shield however you can and bring him down. Once you do, loot his body twice to complete this quest.

791 XP

Equip the E-tech gun and head down into Shock Fossil Canyon again. You have a simple objective: kill 25 Bandits with the E-Tech Gun. Work your way back to the Catch-A-Ride while gunning down all the Psychos that start coming at you. Take your time about it as this gun has a massive clip, but that is also its downside. You can run through your whole stock of the ammo very easily. Just move toward the search area marker and kill whoever gets in your way. It only takes some time, but be sure to loot as much as you can to keep your ammo supply up.

Likely you will run out of enemies to kill. Thankfully there are other side quest in the area that make up for this. Head out to the South of the Doc Mercy's Hideout and go over to the Southpaw Steam & power that is nearby. This is a great place to slaughter the remainder of the bandits. If you run out of ammo though it is best just to head back to Three Horns – Divide and restock at a nearby vending machine.

When you have killed all 25 Bandits with the E-Tech Weapon then the mission will be complete and you can return to Sanctuary and talk with Dr. Zed to finish out this mission.