What is the most difficult ethical decision for a project manager to make on a project?

There might be many difficult decision which differs from the individual managers point of view. From experience the the most difficult decision will be when project began to sink with minimal time left and the fear of late execution fine, the decision of P.M is whether to applyx7 work schedule or add more manpower remains a question in his head. If the P.M takes an early action things might go positive. Second scenario if the Main contractor uses secondary sub-contractor along with his work force, and all of a sudden imagine due to financial crisis or lack of quality the sub-contractor leaves his job or removed by force what shall be the strategy of Main contractor P.M ? whether he shall arrange a separate work force monitored and operate by his team members or arrange a different sub-contractor in no time. These are just two examples from experience point of view.