1. Lock the door to wherever you're playing. If you need to, set up a baby monitor so you can hear her just in case.

2. Depends on what she saw... as she's only 2, this will probably not scar her for life or anything, and she'll probably forget about it soon. I've found that if you don't make a big deal out of something, neither will the kids (at least when they're this young). *shrug*