Think your instructor is wrong - I have had many "expert" opinions which have been utter rubbish.
Vmca demonstrations are extremely dangerous.
I have only done one - started at 300ft over the sea (as pointed out on a naturally aspirated engine density altitude effects it) - we selected zero thrust on the critical engine and I reduced speed - I had on full rudder , opposite aileron and the stick on the back stops with the stall warning going before I lost directional control.
On the ground I argued with my instructor that it was a dangerous exercise - I had been educated far more extensively - he had been a hurri bomber pilot and had left a wing tip on a tree stump in the far east in 1944.
The college stopped the exercise a few years later - there had been several fatalities in the states.
The RAF lost more meteors flying SE exercises than due to real engine failures.
And BEA airtours lost a 707 doing another stupid engine failure exercise.
There are a lot of ill informed people in aviation - read as much as you can including accident reports - and hopefully you will avoid repeating other peoples mistakes.
good luck