The Time Window was a triangular device of Quintesson design that opened a window into time... what did you think it'd do? Extended use of the machine is very dangerous, as it unleashes chronal energy into the universe, which affects time itself. It can cause the past and the present to collide with each other, creating numerous temporal anomalies, such as regressing an adult into an infant or making two duplicates of the same individual. If the process is not reversed, then the entire universe will cease to exist. Temporal mechanics 101.