Isaac had fallen into a dreamless, black sleep after the twins left. He didn't know how long he stayed there but when he opened his eyes, he wished he had stayed a little longer. Above Isaac laid the lid of the freezer. Shear panic took a hold of Isaac when he couldn't open it.
He punched and pushed but it wouldn't open. Unaware that he had shifted, Isaac clawed and scraped at the freezer. His mind was blank except for one thought, Get out! Get out! GET OUT!
Isaac hadn't realized he was screaming, focusing more on the closing space.
Derek went back to the house to see what Duecalion had been on about. Even though he felt like it was a waste of time, Derek wasn't about to risk Isaac's life because he hadn't chased every lead.
So there he stood in the basement of Isaac's house, thoughts of pain running through his head.
For years, Isaac had been beaten and thrown into the basement freezer. He be hauled in for a few hours, all night. A few times, he was in there all day. It had pained Derek when Isaac told him what happened. Now, Derek feared it was happening to him again because the freezer, one of the main sources of Isaac's pain, was gone. Duecalion had taken it. No doubt, he had already thrown Isaac in it.