I mentioned
@a2j04vm0 's spoiler when I was writing my prediction for this gamble's trick some chapters ago, obviously I missed the exact trick being the leap second, but the hints I pointed out are still valid, and the fact that Baku knew about Leader's memory loss meant that as soon as he won against Lalo and the gamble was decided (bear in mind that Yakou was basically in cahoots with Baku the whole time, telling him the game they were playing and all, so it wouldn't have been hard to organize the game to be long enough for the leap second to come into play for Baku) it all turned into a gamble where all that was left for Baku to do was to perfectly manage his time so that the end of Leader's check happened during the leap second, which came down to even the most minute interactions we saw that were mainly in order to manage his time, which is totally doable. This is not as far-fetched as people seem to believe it is, and definitely not too far-fetched for Usogui, of all manga. The foreshadowing was always there of course, and as I mentioned in my prediction comment, the rule about how the clock sound is superior to everything else played the crucial role, so the trick being the discrepancy between the time and the speaking clock was also foreseeable. Now, why does it matter if the trick was a leap second or some tampering with the clock itself? I feel like this trick is just crazy enough to be perfectly fitting for the crazy gambler's last trick (if the match is over, and if it even is his last trick), so it's kind of nonsensical to be upset now about the ridiculousness of the situation. The echolocation as well is not as far-fetched as it seemed, and it makes sense considering Leader's character, I mean, what else did you expect from a super genius whose only weakness was a memory problem? All in all, I enjoyed the ride, and am looking forward to the rest of it now. Let's see if this is even the last act of this game, because even though they said that 5 minutes is the limit, we never know how things will actually turn out...
Edit: There's still a few unexplained things I'm curious about, like the meaning of the blood on Baku's pants, whether or not he was in Eba's building the day of his death, and what the significance of it all was, etc...