Hi everyone.
Well, this is frustrating. I need some help beating the Thief-taker general on Master difficulty with a 700+ custom difficulty rating. The thing is I see a lot of videos and tips beating him lethally (is this a word? ) on easy difficult, with 4/5 blast arrows available. On this difficulty, it's easy: 4/5 blast arrows and its done. All I've seen online with my difficulty rating is the non-lethal aproach. Another here.

I beat the guy non-lethally on my first playthrough. The next one (on easy) I just shot 4/5 blast arrows and he was done (I could take damage and be seen). The thing is I want to beat him till he gets to his knees (not kill him) and then I escape the room, without him wandering around.

I have no focus, can't take any damage, can´t be seen.

But none of the videos I saw work. I only have 3 blast arrows (not the usual "easy" 5). Those aren't enough to kill him. Ok, I just use, on top of those, the 3 sawtooth arrows available, right? Still not enough...even with one more fire arrow, he is still standing (with very low life). When I get to this part, he always sees me when I aim at him another fire arrow, that should be the last one needed to beat him, I presume. Even of he's looking some other way, its like it is scripted that he must see me. I would appreciate any kind of help.

EDIT

I did it! And after more than 40 attempts, I'll leave here a tip. When the "fight" starts, just go immediately to your left, to a more darkened area, to a place where you can swoop-strafe four times in a row and still be in the shadows. Go to an extreme of that shadow area and shoot at the general, immediatlety strafing-swooping the other way, within that dark area. He will shoot where you were when you shot at him, so the trick is to shoot-swoop-wait-shoot-swoop-wait till he gets to his knees. Then you can take your time lockpicking that hard lock. Hope that helps anyone that wants to beat him this way.