The secret base part 2

The cave was surprisingly empty if it could even be called a cave at that point. The inside was actually built like an office space with every comfort one could imagine in modern times. Not only was the electric outlets up and running, but it even had a dedicated ventilation system in prime condition.

That had been the first thing Mark had noticed when he did his first sweep of the place. Every corner indicated that someone had likely been here and had used this pace recently. 

Why had his system led him here?

The only thing peculiar about this whole situation was the lack of communication equipment inside the place. There was no computer, no control panel nor any telephone. Even the communication signal had been cut off as soon as he had entered this part.