The locked gate on the right when exiting Iosefka's Clinic is unlocked by progressing through the Forbidden Woods and also allows the player to access the back of Iosefka's Clinic. To access this locked area, waken at the Forbidden Woods and head straight until you reach the town area with the dog cages on the left side. After you kill the dogs, there is an obscured path off to the left which leads to a cave. In the cave, there will be a poison swamp and some giant enemies that you must traverse to reach the small passage with the ladder that takes you to Iosefka's Clinic in Yharnam. Once here, you may unlock the gate and head to the back where there will be a Celestial Host. After killing the it, climb the ladder to the roof and kill the carrion crows. Now, enter the open window into a hallway in the back of Iosefka's Clinic. If you sent any NPC's to Iosefka's Clinic, you will find them as docile Celestial Mobs which drop some items. If you turn right, you can open the door to the main clinic room where you will find the Cainhurst Summons key item, which allows the player access to Castle Cainhurst. If instead you turn left in the hallway, you will find some items in a room, as well as a separate corridor area where the player will encounter Iosefka who warns the player not to approach. If the player approaches, Iosefka will become hostile and the player will not be able to speak to her from behind the double doors any longer. If the player enters this area after the Red Moon event has been triggered by defeating Rom, the Vacuous Spider, Iosefka will instead be found in a non-aggressive state on a table. Killing her now will cause her to drop a One Third of Umbilical Cord consumable item.