User blog comment:Linathan/Squad Spotlight & Guide: Trial EX8 - Genius' Challenge/@comment-1389361-20160728023808

Also note: once you spotted "Overdrive" on the screen and haven't used your own Overdrive yet in the previous turn, then you have to use your Overdrive and Fujin because simply, there is no time to build up the UBB gauge! The next update might be cool to display HP threshold, but then, this trial has many opponents that spawn one after another, it's hard to maintain all of their HP threshold into a certain percentage.