Harlin never felt so helpless against an Evil Spirit.
It was the first ever time where he felt like he could do nothing.
The Evil Spirit held all of the control.
It did not matter whether it would spare Harlin after he did what it wanted.
All that he could do was hope that it did spare his life even if it was for a moment longer.
Harlin could not think of another way to solve the problem and the Evil Spirit was the one that held most of the control.
It was the one that would decide whether it would kill Harlin.
Perhaps it would kill Harlin the moment after it got what it wanted but it was better than having his death weigh heavily on the mind of Sloane who did not wish to be the reason why his ally was killed.
If he was stubborn and refused then he knew that the Evil Spirit would kill Harlin without hesitation.
Even if he used his ability, there would be a limit to how much he could achieve.