At this point leader pulled a "i discovered your plan and i cornered you", he guessed the thought of the people on the developers room who were still at the most basic logical thought, thinking Baku had the lead (which he actually had but not as what they thought), then he manipulated yakou into giving his all for the revival trying to outbluff Baku into thinking that he would pull the same startegy before him. 
The next round, Baku who played as "C", instantly checks to disguise himself as actually wanting to die, leader already let the handkerchief and then revealed baku's strategy and then bluffing that he would make it before him. Baku had to play this move to control the clock's time for the leap second and at the same time linking this to the thoughts of souichi. His actual plan after leader's first near death was: make souichi believe he hasn't safe strategies anymore with his aura-->in the next round checking at ten seconds and keeping the bluff of the 3 near death strayegy inducing souichi to instantly drop afterwards ---> checking instantly the next round to make all things connect from souichi who was being perfectly keeping with this (fake) thoughts. 
(4th round 2nd half) At this point leader obviously with full pride he was trying to take some squandered time to make it look like he would near-death afterward and pulled the "TSK" trigger for the echolocation making it to match his speak, he checked after 35 seconds of squandered after Baku dropped the handkerchief. 
Baku kind of drove the conversation to be a check for leader around 30 seconds (35 seconds) to keep clocking that mf leap second, leader also wanted to take some squandered time for his next bluff and at the same time making it like a mind game with Baku while in fact he was using echolocation (baku had to match souichi's thought so he kind of acted in leader's destiny speak and already dropped the handkerchief trying to fake the fake mind game of souichi). 
At this point Baku's heartbeat was still fast disguised in the nervousness of having to die to reset his cylinder to have more possibilities, leader right now with the convinction that everything went like he predicted proceeded, in the 5th round 1 half to drop instantly the handkerchief to stop baku's instant check, baku's disguised plan worked as he made souichi do an instant check making him believe his own bluff, while the others in the developers room thought that Baku had the upper hand since his instant check succeded, souichi then explained baku's 3 near death strategy and manipolated yakou into giving his full determination into revival since he was weak, to deceive Baku into thinking he would die first in the next round; baku who completely drove souichi in this plan he knew that souichi won't turn the next round an proceeded to act and make it look like souichi outbluffed him (in fact at this stage of the game he knew souichi would start to use echolocation beacuse the "tick" sound from the phone clock was lowered before). 
Baku's 3 near death strategy who was just a disguised plan and a layer of the leap second strategy, confirmed souichi was trying to outbluff him and not turning in 5th round 2nd half and so Baku dropped the handkerchief at the start knowing souichi wouldn't turn and faking it as being deceived by souichi; leader who expected this from the 3 near-death strategy (not knowing baku's true intentions) in fact didn't turn and he used echolocation and checked at 15 seconds which is a reasonable time giving the fact that by baku's sentence (Baku was acting), he confirmed that he throw it so he "TSK" at the first interval of 10-15 to confirm it one more time, this was reasonable as he didn't want to draw much squandered time so for souichi he thought that for Baku it appared like: baku "i was being outbluffed by him and already dropped the handkerchief so in fact he only turned at 15 seconds to be sure"- with this "baku's thought" in souichi's mind he expected Baku to not find about echolocation. On the other way, Baku kind of predicted this interval as in the next round when souichi was "C" he dropped the handkerchief instantly to stay in line with the time. After this it was the 6th round and again Baku checked instantly, to remain in line with his previous fake plan on dying 3 times and to make it look like souichi could actually die in the next round with this souichi who was guided by baku's true intentions hidden in his actions, he didn't dropped the handkerchief to show that in fact he from the beginning didn't want to die and at this point he would have let Baku die knowing that the probability of Baku being alive considering yakou's weak state and broken hand for the revival; all of this was the outcome that Baku wanted thanks for the fact of faking his 3 death plan to let souichi outbluff him when in fact it was Baku who deceived him so that he would die for his 2 near death and ,counting the time of death and the revival, he would enter the route of the leap second. This was the plan, from souichi's near death and it was esecuted to make souichi's squandered time enough and his turns to be clocked perfectly knowing that if leader discovered the 3 near death plan he wouldn't actually die since he wants a perfect victory and for him dying another time wouldn't let him achieve that and also because of yakou condition, so Baku who instead gained only a low amount of squandered time thanks to his fake plan and souichi's actions who was guided by Baku to enter the leap second route. After Baku deceived souichi who is now convinced that Baku would go for the 3 near death game, this would let Baku counterattck again after his revival. In baku's flashbacks in his 2nd near death, Baku saw the path leading to the leap second (this foreshadow is revealed after the leap second) confirming that Baku now entered the route and succesfully deceived and guided souichi. 
After this souichi who had checked correctly until now and since his previous checks weren't noticed by Baku (baku knew about him using echolocation but he had to fake doing the 3 near death plan, to not let souichi die but to let himself enter the route,he instead controlled souichi's squandered time to be enough for the clocking giving leader the impression that he don't Know about echolocation) adding baku's condition after his second near-death would let him have the advantage, or atleast that's what he thought. 
In the 6th round 2nd half, Baku who was "D" who had to continue bluff the fact that he don't Know about echolocation to have souichi thinks in this logical way: "after 3 successful checks with low squandered time, Baku would think i have to take a breather and instead he has to drop the handkerchief the accumulate squandered time but if he thinks i will do another risky check he wouldn't drop it" from this thought Baku who is supposedly in bad condition after the death and being supposedly outbluffed by souichi, he would think souichi would take a breather after 3 consecutive succesful checks and have to accumulate squandered time, but that would be logical only if he didn't know about echolocation moreover he has to make souichi think like that, so instead he dropped it instantly and accumulated 8 seconds of squandered time making souichi thinks he has the advantage and at the same time coinciding this with the time for the leap second. 
Now that he made souichi having the advantage the best linear thinking for this is to make souichi trapped in this fake thought created by his aura and guiding souichi into thinking that he would discover immediatly when the handkerchief would be dropped but his real purpose is to make souichi drop it instanly to accumulate squandered time to farther his leap second plan making it look like it's souichi's advantage (this was the best play, since souichi who thought he had the upper hand until now and who lead Baku into near death and having echolocation, he wouldn't suspect baku's other reason, behind this play, in the 7th round).