The meeting room had walls made of shiny metal, as it was made from the alloy used to create Precursor ships. It was Ashton's decision to refurbish one of the ships as a meeting room while the others were reconstructed with the help of Orions and Xyrans.
The creation of the room served as a reminder for them of the enemies they had conquered and survived. Every time a being capable of threatening Earth's safety appeared, it was evidently defeated, and its remains were stored in a separate section of the room.
While some might consider it inhumane, for Ashton, it was merely a statement of power. However, the only thing the room lacked was the remains of a precursor... something Ashton had been itching to get his hands on.
He had never revealed that desire to anyone, but it seemed fate knew exactly what he wanted to do and gave him an opportunity to fulfil his wishes.