Step 1: FLY the plane...don't get caught up on checklists or ATC.
Step 2: Is this bad day about to get worse:
How long is the runway? What are the weather conditions? Is the cargo compartment near the engine that had a fire indication? Am I about to pull a ValueJet (they had a FAST fire)?

If you decide to continue the approach...have the Pilot not flying run the checklist while you contine to about 1000 ft AGL...then help you with what you need.
Hope this helps.

P.S. Why did the instructor say you needed to run the check list? He may have some good information to consider...but if you had all that AND smoke in the lav now...you don't have much time...in my oppinion
What type of training is this? Is it part 121? If so...I do not believe they are allowed to give you multiple (independant) failures for a check ride to this level. Check to see if they are following the standard training program.