Complex sentence: When the Sole Survivor accesses Bradberton's office, they discover a hidden elevator leading to a private Vault and Bradberton's still-living head attached to a life support machine after two hundred years; punishment from Braxton for doubting the military.
Split into simpler sentences: When the Sole Survivor accesses Bradberton's office, a hidden elevator leading to a private Vault is discovered. Inside the Vault is Bradberton's still-living head attached to a life support machine as punishment from Braxton for doubting the military.