Luke:
As Luke was checking on his troupes all he could think of was the man that was strapped down on his table. He really didn't know what to do with him. Of course he could always release him, but for him it wasn't an option. Just the thought of realising him and giving him the opportunity to fall in love with someone else wasn't a thing he could live with. He knew it was selfish but if he couldn't have him no one could. Actually it wasn't that hard, it was rather easy he just had to push the button and he was good to go. Then he could go home to his kids and his wife. See it is easy he decided I... am...just ...gonna...press.. And then the power failed. Of course he could always start the emergency generator but this gave him the perfect excuse to go home and think about it so that's what he did.
After this long day even his children and wife Annabeth couldn't brighten his mood and the guilt certainly didn't help .The guilt of leaving Percy there and even the slight guilt of more or less betraying Anabeth. When he tried to sleep he couldn't hold it anymore so he went back to his so called "crime lab". If he killed Percy he didn't have to feel any guilt anymore cause Percy isn't alone in a dark building anymore and he is theoretically not cheating on Annabeth. So he just was going to push the button...But he couldn't and pressed the button to release him cause a live without Percy is no life.