The cat heard a scream and inspected the area, when the cat saw the broken glass, it assumed that the babysitter was trying to hurt the baby. It is likely that this cat has known the baby since they were an infant and feels like it has some kind of parental role in the baby’s life. The cat just casually came up after hearing the sound of the broken glass and screaming, it then inspected the scene carefully and decided to act. The babysitter knew that the cat was only trying to protect the baby, so she was trying to show the cat that she wasn’t hurting the baby towards the end. The babysitter is probably okay after that, cats can really mess you up if they want to.
