In ancient Rome, Romans did not build rooms called vomitoria in which to purge themselves after a meal. Vomitoria were the entranceways through which crowds entered and exited a stadium.
Nero did not "fiddle" during the Great Fire of Rome (violins had not yet been invented, nor was he playing the lyre). In fact, upon hearing news of the fire, Nero rushed back to Rome to organize a relief effort, which he paid for from his own funds. He also opened his palaces to provide shelter for the homeless, and arranged for food supplies to be delivered in order to prevent starvation among the survivors. Finally, he made a new urban development plan that attempted to make it more difficult for fires to spread. However, it is true that he blamed the fire on Christians.