Hi,
When I did my assessment we where told to deal with the fire drill as we had done in our previous aircraft be it a Seneca or a B737 or L10-11 that you did you MCC in.
Just have good MCC during the failure and confirm everything with the PF before moving the switches.
I was lucky I knew what to do since I did my MCC/JOC on a B737-400 so called to my partner what switches to pull after we both agreed they were correct.
But if you are really stuck sure the assessor will help you out with the engine failure. I think at the point they are looking for good CRM.
All the best