Whatever the reason for your bitchs behaviour, and as you can see it is very hard to determine without meeting her, never show any reaction at all to it. Ignore her and if possible leave the room and leave her to it! Don't give any eye contact and don't say anything. Do not give her any attention or eye contact, or re-enter the room, until she has been calm for about ten seconds. If she is having you on expect it to get a little worse before it gets better.