Why did Drona, Kripa and Bheeshma remained quiet during the disrobing of Draupadi?

Why did Drona, Kripa and Bheeshma remained quiet during the disrobing of Draupadi? Bhishma: When Draupadi asked Bhishma why the daughter in law of Kurus is being treated as slave and did Yudhishthira had a right to stake her if he had lost himself, Bhishma replies that whatever powerful people say becomes dharma and the opinion of weak does not matter and it carries no influence. He then directs Draupadi to ask Yudhishthira whether she is slave or not. Yudhishthira keeps mum and Karna declares her as a slave stating whatever slave earns belongs to the master and wife of a slave cannot possess anything on her own. What in this world a strong man calls morality is regarded as such by others, however otherwise it may really be; but what a weak man calls morality is scarcely regarded as such even if it be the highest morality. [1] Drona: Drona didn’t had any powers in the Kurusabha to cast his decision. Drona was employed by Bhishma and was getting salary from him. When Bhishma himself did not oppose the act, Drona being a mere teacher and an employee of Bhishma did not raise his voice and he held his head down in silence. Drona did not speak a word fully knowing the response he would get. Kripa: Same applies for Kripa. Kripa was taking care of the royal duties of Hastinapur kingdom and did not have any special power to stop Duryodhana