In my story idea one of the things my serial killer does is remove her victim's adrenal glands(she has illegal organ harvesters do this), then put him in an underground maze and see how far he manages to make it out of the maze before he collapses and dies. This character dies.
For instance, a five minutes stroll and he's out then he's probably alive at the end. However, if it's a long arduous maze and he's being chased by a serial killer, the victim will burn through their hormone reserves much faster and would be more likely to succumb to death more quickly.
Hope this help. Your book idea sounds very intriguing!
And shout out to Liz for helping me with this question.