i'm not sure if this is common knowledge, but most of the runs i saw seemed to be reacting after they saw the magitek terminal finished, so i thought i would share this!
The terminals pulse 7 times, with 3 seconds between each pulse, and 3 seconds after the final pulse before the countdown completes. Depending on when exactly you enter the terminal, the exact count may or may not line up with the duty timer, but watching the duty clock tick down can still help you get a feeling for the timing even when the terminal is misaligned with the timer. Every terminal in this instance follows these same rules! This is particularly helpful for blue mage, since our "dash" (loom) has a cast time, so I start casting after the 7th pulse after 2 seconds, but I tested it and even with ninja you can Shukuchi at about 2.5-3 seconds and blink away as the countdown finishes, rather than having to react visually to seeing the countdown finishing!
hope that helps some people! ^w^