Answer:
Negative reinforcement
Explanation:
Negative reinforcement is a behavioral psychology principle that occur when one's action allows  him / her to escape an unfavorable action before it occurs.
It is mentioned in the scenario that Sheppad  is being bullied and criticized  by Alexandra  , being the boss's sister .
Susan's idea of completing all work including the extras is a behavior intentionally put up to escape the constant unpleasant stimuli from Sheppad.