 Sometime after Walter brought Peter from the parallel universe, William convinced Walter to allow him to remove pieces of Walter's brain and implant them in other patients to keep the knowledge of dimensional travel safe; this process led to Walter's mental instability and institutionalization.The two parted ways, William going on to form Massive Dynamic.Sometime after founding Massive Dynamic, William finds a means to travel to the parallel dimension, and sets up an office in the still-standing World Trade Center.