I didn't catch that the bathroom door was closed. They don't like being isolated. It's scares them more, I believe. I would really urge trying to find room for an x-pen, put a sheet of vinyl under it, or even a vinyl shower curtain. Otherwise, a baby gate would be good - preferrably one that she can't climb up over and fall and hurt herself. If you don't change something there, the bathroom door is going to be destroyed and you're renting an apt, so you would be responsible for the damage.
