The Destruction of the Chariot
The more Sebastian thought about how he could kill the tier-2 fanged and the more he saw the problems in it. What if he missed? What if the beast saw him and chased him? He would have no way of surviving at that point.
Besides, he also had to retrieve the bolt and the mana cluster, so the situation would not be the best.
<The only viable solution is to lure it the walls.>
But that itself had problems, too. The first obvious problem was how to access the wall; it was not straightforward to approach it due to the likely state of the buildings around there.
The debris would make going there hard, and the fangeds would make things harder.
The second issue was how to bring the ballista up to the wall itself; the weapon was a large and cumbersome siege weapon, after all. It required careful handling and transportation, or it would just end up destroyed on the ground.