If an 80kts airspeed call shows an out of limits difference between the PF and PNF ASI then it is a Command call to abort, gently, no rush, no need for reverse thrust above idle, or RTO brakes, yes?
What the standby ASI is reading is often not relevant in todays modern aircraft as it is possible to dispatch, according to the MEL, without it, it is no longer considered vital in, for instance, the B747-400 due to the amount of Independence and backup that goes in to the two main systems.
This is my humble opinion!
So I would suggest that building anything more than an instrument failure into this situation in the SIM is departing reality.
If you really want to roll a grenade into the 'box', when all the checking is over, then a generator failure at about V1 minus 10kts should do! This may result in a high speed abort, a wheel well fire and a pax evacuation, thus bringing the session to a successful close!