Olivia and the others observed the battle that was going on in the air. Although they were already quite a distance away from the area where the fight was taking place, they could still feel the intensity of that battle.
The high temperatures from the flames that were being controlled by Henry could actually be felt from where they were currently at. And if there was just a normal person where they were, they would definitely be already scorched.
It was only due to the fact that none of them was a normal person, but instead, each and every one of them was a warrior, and that was the reason why they did not feel that much pressure from the high temperatures in the surrounding areas.
The only problem was the fact that the temperatures kept on rising as the fight between Henry and Ezekiel went on. Additionally, the area where the two of them were fighting was actually being completely devastated.