Without experience, 80 hours doesn't seem like much... however, they may have seen something in you that made them think you could handle it. I know in my ED, our fastrack/urgent care area has 1 RN, 1 tech and 1 ARNP or PA-C working at any given time. Out of experience, I believe 80 hours of orientation is definitely do-able.
If there's a skill you aren't familiar with (like splinting or wound dressing) the tech will most likely know how to take care of it...and depending on the techs attitude, you can ask them to teach you how to perform these skills.
If there is a patient who's physical health has you confused, the PA's and NP's will be there to help.
I always feel that in the fast track area the main role of the nurse is to assess the patient, decide if they're sick or not sick (which is done in triage already), communicate the problem to the provider... analyze the providers orders, question the orders if you disagree or need clarification on them.... carry out the orders... delegate the tech stuff to the techs.... understand the medications you are giving and what they do what they do.... decide if the treatments worked or not.... then ship them out.
It's definitely overwhelming at first, but you WILL be good at it eventually... one day you will think "I got this!"... then the next day you will think "Omg, i cant do this! I dont know what i'm doing!"
Just remember, it's difficult to harm someone in the fast track area, especially if they are attached to your main ED. If you are unsure of something, DONT GUESS! Ask someone...if they dont know the answer, then ask someone else.
Also, like another poster said: keep a notebook.