Is it alright to pray Fajr Salat before the Adhan, if as a doctor, I sometimes have to continuously work not able to pray after the Adhan?

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions. It is unlawful to pray Fajr before its designated time. If it is impossible for you to perform it in its designated time because of a necessity approved by Shariah, like saving a human whose life is protected by Islam (such as a Muslim, a Christian or Jew living under the protection of an Islamic state or a person between him and a Muslim state there is an agreement), it is not objectionable to delay the prayer till the time the necessity is removed. However, you should hasten to perform it as soon as the necessity is removed. The scholars declared that the person who works to save the drowned is permitted to delay the prayer. Allah knows best.