I'm going to let the incident go because honestly, I'm too tired, overworked and pregnant to start over looking for someone else right now!
If you're tired now and don't want to deal with it, just wait until you have a newborn at home, are exhausted from getting up 3x a night, and end up using a chunk of your part time hours having to put out the fires from this woman's latest antics. Eventually, she'll start getting away with more and more simply because you aren't there to manage her every minute of the day.
There are tons and tons of journalism and PR grads with good experience out there that would love to have this job, who would be better team players, and with whom you would feel very comfortable and confident while you are out of the office. Think about it.....