Was fortunate enough to take the jumpseat recently on what was a command training flight with training cpt in right seat and co-pilot in the left performing as captain.
Throughout the flight the training cpt made several intentional mistakes, and it was interesting to see just how much the stress level could rise, e.g flight director switched off just after take off, FMC "broken" at top of climb,(and u/s for remainder of flight) "autobrake set" (to "0" ) for landing....
On the return flight nothing "happened" until the landing checklist was called for, after calling for it twice the only response from the RHS was "I'm dead", all in all an interesting days flying.