The Underground Chamber is an underground laboratory constructed by the ONC and located beneath Seal and McGrath's research lab without the former's knowledge. Here, the ONC conducted experiments on McGrath involving the use of his Life Saver. Seal, alongside Nash, Dax, and Jason, discovered the lab during an attempt to rescue McGrath.
Later on, chancellors Winters and Sydney conducted tests on their own soldiers using an invention they call "the pod". Combining the Life Saver's energy with the pod, the chancellors created their own method of human augmentation.
The location first appeared in Loved and Lost.