Derek opened the door quickly and let Rick's group enter the mansion. That backdoor didn't lead to any room in particular, though. Instead, they faced stairs going down right after they opened the door.
'Just as I thought, this mansion is a facade. This backdoor is, in reality, the door to an annex. People here are very good at creating this kind of thing, huh?' Hector was impressed by their creativity.
The group went downstairs. For a moment, things were a bit unclear around them. The illumination was very poor. They never were 100% sure if there were more stairs or not.
Those stairs went so deeply on the earth that they needed nearly ten minutes to go all the way down. Hector and Kevin were quite impressed by that. Rick and the others knew why that annex was so deep in the earth.
When the illumination became a bit better and they could discern their figures on that pitch dark place, the group could finally see where they were.