Pharaoh turned back to strive to disprove the miracle of Musa (pbuh) after he had seen the greatest sign. Despite the gentleness in Musa (pbuh) response (And let me guide you to your Lord so you would fear), Pharaoh meet it with violence and terrifying.
Then, who is the terrorist? Who is the extremist? Pharaoh or Musa? The believer or the disbeliever? Certainly, the answer is very clear.