Aziz's pride

Among the three choices, walking away was not Sheyan's style. He gave it a pass.

As for helping the sniper/summoner that he was not acquainted with in the slightest, while he already had the upper hand, helping him may not result in him showing any gratitude towards Sheyan. Sheyan wasn't willing to paste a hot face to a cold ass either (Chinese idiom meaning to show warm feelings but meet with cold rebuke). Not to mention, in this cruel Bloody World, everyone came in here to kill or be killed. Even if the sniper/summoner turned out to be a righteous person, would he really let Sheyan off when the going gets tough just for this small favour?

That's why, after deliberating, Sheyan found that the most suitable choice was to help Aziz!

The main reason being: they were from the same realm.

The second reason being: Aziz is a very prideful person. A big characteristic of him was that he wouldn't owe someone.