Examine the asylum's documentation | Chapter 5: The Forsaken Thief Guide

Note - You can reach the central part of the Women's ward [Moira Asylum - Women's Ward] either through the building's ground floor (the dining hall and the neighboring rooms) or by using the key that you have found at the Men's Ward. Both of these variants have been described in reach the Women's Ward and Find the key at the Men's ward, respectively.

The document that you are looking for

Which way of entering the Women's Ward you select, does not matter, because you will have the freedom of movement around this location and there will be nobody to obstruct you. Just like in the case of the Men's Ward, I recommend that you start by exploring all of the corridors, because you will be able to find there a Syringe - 6G and a document (Lessons). Go now towards the central, Southern room and examine its wall, where you will find a box. Use the wirecutter to sabotage it. You can now enter the proper room. The most important thing to find here is a document (Patient Transfer), thanks to which you will learn that Erin has been transferred to the treatment center (at this point, your objective will update).

I recommend against leaving the Women's Ward at this point because, just like in the case of the Men's Ward, there are many valuables to find here. Start with exploring the rest of the central, Southern room to find a Tea Pot - 12G, an Ink Bottle - 8G, a Pen - 10G and two documents (Patient Notes and Aggression Again). At the same time, note that Garret can climb here, thanks to which he will access the hole, under the ceiling, shown in the above screenshot.

The central, Northern room

After you take the hole described above, you will end up above the main corridors and you will be able to reach, thanks to it, the rooms that cannot be accessed in any other way. First of all, jump to reach the ledge above the Western cells and find the opening, thanks to which you will make your wait inside one of them. In the neighboring cell, there are Scissors - 5G. Once again, return to the upper ledges but go North this time. Jump and find the opening in the wall of the central room. Jump into that location, which will start another vision. After you regain control over Garrett, collect the Poppy and the Pocket Portrait - 4G.

One of the side rooms

Leave the exploration of all the remaining rooms, located in the Eastern and the Western part of the Women's Ward, for the end. This will allow you to find Scissors - 5G, a report (Report: Patient #18), three notes (Reporter's Notes, Heat and Cold Treatment and Huntfield's Illness), a Fork - 2G, Hand Mirror - 8G, a Pocket Portrait - 4G and a Tea Cup - 2G).