The situation with kensei is rather special though. Based on what we saw against the bear it is perhaps in principle similar to what miu seems to go through however there are significant differences to consider. For one thing, akisame did mention ishinsai had an obsession of sorts with dou ki to begin with. For another miu is by no means an actual deranged murderer. Miu is about as nice as you con conceivably be in this manga. In turn merely this ki thing activation is more than enough to make her lose control enough to actually kill another human being. To put it in perspective just look at sakaki for instance. He is the sort who would willingly and gladly beat the shit out of someone. He is a dou user who has consistently fought people more than willing to kill him and yet as kenichi noted when he was fighting akira the guy never once shows murdering intent. While the mountain training did seem to suggest there were some dangers to dou ki (which if I recall did seem to be circumstantial though) nothing would have suggested that at an advanced level it could be dangerous for someone who is not insane.
LMFAO!!! that chapter was hilarious
at first i thought Shiratori was coming out of the closet
but no just a girl....wow smh that was funny as hell
The elder was suppressing miu's ki of dou, but she showed some kind of proficency in it even before junazard's training (for example the battle between sakaki and hongo where she excites herself in order to see the shockwave's orbit). Probably the elder's aim was to make her slowly master her ki until she was able to fully release it.
^Saiga is a Dou ki user? Do we have enough information to confirm that?.......if so show me a link please
I don't think the issue with miu was that she had proficiency at dou ki but rather that she was a dou ki user from day 1 of the manga. She was stated to be a dou user as kenichi was in the ki crossroad thing during the mountain training.
There is also barely any mention of sakaki and apachai going berserk. Ok, apachai had trouble controlling himself and the flashback showed sakaki had trouble with going too wild in fights but even in those extreme scenarios the situation did not even compare to what we just saw with miu. Apachai has never actually killed anyone and in the situation of kids and animals he is innately able to restrain himself. Sakaki goes wild when he fights and has a talent for getting pissed off but he still has never lost control in a manner which would kill someone. Even kenichi has noted that sakaki has never had any murdering intent in him. And its not like sakaki was dealing with lowly criminals in his youth either, he was dealing with weapons and drug dealers and even then he never killed anyone. In particular with sakaki there is never any mention that he ever lost control like that and even when he has lost control he has never killed (the master politician).
There are two situations in the manga which seem similar to what miu has gone through. The first is that guy natsu fought while training under sougetsu before he became a yomi. It was a huge muscular dude who sougetsu said natsu had to defeat in a few minutes. In that particular case sougetsu said the time limit was the time natsu had until his enemy's dou ki becomes too large for him to handle thus natsu would die. The second would be perhaps pengulu sakan who had some similarities with the guy natsu fought. He was just a mindless fighter bent on killing.
Not to mention that by the time saiga decided he had to spill a little blood he was already a grown man and master class fighter. I doubt this is the sort of thing which masters have trouble with, it is the sort of thing which appears to be dealt with earlier on taking miu and pengulu in consideration.