Cranky lady at work>?

I work for a call center today was my 1st day I trained with this really nice lady. and then she went home for the last 1 1/2 hrs i trained with this psycho. She was doing tech support for some computer system which was totally foriegn to me anyways I just listen in. But she was so crazy she told me all the customers are stupid and she couldnt believe they dressed themselves in the morning. then she just stared at me, like...er what was i suppose to say.. i just nod and was thinking OMG what freakin crazy woman. Anyways It was really uncomfortable she kept downing the customers and when they would be on a call she would mute it and make fun of them..it was so disturbing. I know ur not supposed to act that way in front of new ppl..Question is i dont wanna be a snitch? But if they put me with her again? I dont think I can handle it shes so cynical and u can tell shes burnt out..what to do ? advice tell boss or no???