Why did the Ultron bots flee?

Question

In Avengers:Age of Ultron, during the final battle that ensues in Sokovia, Ultron faces the Avengers guarding that thingy which held the city of Sokovia and prevented it from falling:

Thor: Is that the best you can do?

(Ultron summons his army of robots to join him.)

Steve Rogers: You had to ask.

Ultron: This is the best I can do. This is exactly what I wanted. All of you, against all of me. How could you possibly hope to stop me?

Tony Stark: Well, like the old man said. Together.

(They fight off Ultron's attacking robots.)

Ultron: You know, with the benefit of hindsight...

(Hulk knocks him far away.)

Just as Hulk punches Ultron away, he roars and the Ultron bots flee immediately. Ultron (and his bots) evolved over human imperfections. As Ultron puts it:

Everyone creates the thing they fear. Men of peace create engines of war. Invaders create avengers. Parents create children, that will supplant them.

So evidently, his programming overcame the concept of fear. But when Hulk punches him off, the Ultron bots flee in fear. Is there a reason why they ran?

Answer 1

Retreating is not only a product of fear. It's also a valid strategy. Not saying there wasn't hypocrisy in his philosophy, but lets consider the scene in question:

By this point in the movie, Ultron had become aware that he was clearly outmatched in a head on confrontation, but his primary plan was still on track. The world would be destroyed, but he still needed to be around to survive it. Since he can no longer flee through the internet, he needs a direct presence to recreate himself, which means he needed at least one bot to survive.

If anything, fleeing here actually improved the odds of both plans succeeding since the Avengers must now divide themselves between stopping him or stopping the kinetic weapon that was Sokovia. They also served as a distraction from the broken bot who ends up triggering the weapon. All he had to do was play dead.

But strategy or not, this doesn't invalidate the question of whether he actually overcame fear as he claimed. Vision doesn't think he has:

VISION: You're afraid.

ULTRON: Of you?

VISION: Of death.

Answer 2

They weren't fleeing, they were escaping.

As evidenced repeatedly earlier in the film, Ultron is present insofar as any of his bots are. He goes out of his way to destroy himself, using himself, twice to prove that to the Avengers! The Avengers clearly understand that if even one copy of Ultron escapes, then all of Ultron will have escaped:

Thor: They'll try to leave the city.

Tony Stark: We can't let 'em, not even one. Rhodey!

Once the battle turned against Ultron, he attempted to escape so that he could regroup and fight another day. Any one of his bots escaping would have sufficed.