When Alex reached that place he could see the fight was going on and he really did not expect that none of his attacks would be able to harm that person. Actually not only harm but he was not even able to damage that person with his power. For the first time he was very shocked and couldn't believe something like this.
But one thing you can say he was sure about after this that everyone of them were above his power level. Because of this he is also unable to see the status of those people and because of this he is unable to damage any of them.
Actually, Alex already guest something like that from the start and because of this from the start he did not have the main motive to Injured those enemies but he just wanted to attract the attention of those people toward him so that those other people get the time to attack those enemies while those enemies will be focus on him. Well the thing was that actually that plan did not work that much.