At first, Evan was not planning to get involved in the fight of two B rankers, because he knew if anything goes wrong, and they caught up to him there is no way he will be able to fight against them.
But after seeing the wolf get the points of Mars and his teammates Evan had no choice but to take action.
Leon already has more than 7800 points, if he killed the wolf and gets those points as well he will have more points than him.
If Leon got those points he wasn't sure about surpassing him again.
Even though he knew he is no match against any of them in a head-on fight, he can still kill one of them if he use his shadow bullet perfectly.
To not get caught by them, Evan first distanced himself from them so that after taking the shot he can run away quickly using his shadow walk.
After arriving two hundred meters away from them he created a shadow bullet using sixty percent of his mana.