A single use of the Sever divine ability costs 4 units of spiritual energy to use. As a normal rank 2 killer, they should only have 20 units of spiritual energy in total.
So they can only activate Sever a maximum of five times. Death Marks also require 1 unit of spiritual energy, which further reduces how many times they can use Sever.
If they use each activation of Sever to attack at least two times, then they will be able to accumulate the six death marks they need by activating Sever three times. That way they would have only spent 18 units of spiritual energy.
So they should have 2 units of spiritual energy left after their combination attacks. It is reasonable that they are already worn out and finish what they started.
Fortunately, they were not fighting alone. The sergeant took advantage of the situation by casting his own Shackles divine ability on the giant.
