They saw movement close to their ally's destroyed head.

An eldritch monster was born next to Flat Escardos, almost ridding everyone who saw it of their sanity, and jumped to the nearby buildings.

It was Heroic Spirit Jack the Ripper's last stand.

However, the Heroic Spirit let his emotions get the better of him and overexerted his power, crumbling to light dust before he could reach the building's rooftop.

His magical energy path was severed, so he couldn't maintain his form.

They didn't know if he was completely terminated or forced into spirit form.

Either way, with his Master dead, he was bound to die out unless he formed a new contract.

Fate/Strange Fake: Volume 7, Chapter 21 ("Beings Shaped In Man's Image I")