If you find a knife, don't stab someone. For a good reason.
A Plague Tale Requiem Walkthrough: Chapter 1 Under A New Sun – 100% completion
If you are in Chapter 3 of A Plague Tale: Requiem and you are escaping from the fort, you will come across a closed workshop. In this guide, we'll teach you how to open it and what you can find inside.
While escaping during A Burden of Blood, one area you must visit is a large barn with a hanging ballista. In it you'll find a workshop that the game won't let you open right away.
To access it, you must sacrifice a knife – which you must have found beforehand as loot and not used on enemies. Knives act as consumables, so if you use one, it will be lost.