In the scene where the mice are floating in the glass cage and the actress reaches in and holds one of them, the mice were transported to set in a travel container by the trainer.
One mouse was placed in the cage and placed directly on the vertical Wire mesh. The mouse is allowed to walk around the cage displaying natural behavior along with climbing the mesh. The footage will be used as reference footage for post production. AThe actress may be seen giving the impression she is reaching in and touching mice that will be added in post production.