frenchani finally clarified it for me on salonvirtuel.

I know why I was confused. What I saw was Mercedes coming to the shed screaming Pedro, seeing the prisoner, pained. The shed doors closing.
The next scene is of Mercedes depressed with the kitchen helpers and contemplating a way to get out of there. In short it may have been clear in the screenplay, but was not clear in the film to me. Then again I was admittedly distracted.

Thank you for the clarification.