Answer:
I will report the Field Training Officer to the higher authority.
Explanation:
If I was rookie police officer and are riding with a Field Training Officer (FTO) and he was drinking while on duty, I would report it, because he is endangering my life and his and others around us. It is important to note that irrespective of previous evaluation or submission made on me by the FTO, it is unethical for any trained police officer to take any amount of alcoholic drinks while on duty. Because when someone is under the influence of beers, he/she does not function effectively and may act abnormally.