Who has done more to earn that privilege than Taim? Trained and brought a large number of channelers into the fold. Is in a somewhat trusted position close to Rand. Honestly I think, other than Ishy/Moridin, Taim has done the most good for the DO's cause.



From WH, Out of Thin Air, "Dashiva had simply vanished." No contact with the Asha'man after they get to Far Madding. I think Taim believes that he is the only one who ordered the Asha'man, that or he believes that they won't reveal his plans to anyone. Whereas Slayer is an unknown quantity to him and Taim can't predict what Slayer might do with the info that someone besides a Forsaken knows how to summon him. I would think that Taim received the info directly from the DO. Even if Moridin told Taim, Moridin is the one Forsaken who is above the games the others play since he actually is totally for the DO, not the promised power that the DO's success gives the others, therefore he's not a threat to Taim.



Janduin is a terrible example. One, Slayer is only hanging out with some Trollocs and happens to end up fighting Janduin. Then, he wins because Janduin refuses to fight someone who so closely resembles Shaiel.



It's unlikely she'd use Compulsion since a man embracing the Source is apprently immune, from Sammael's thoughts in LoC and Alanna's inability to compel Rand using the Warder Bond in LoC. So instead of trying to capture him, since she has no way of knowing about his shield she quickly eliminates a possible threat.



What part makes it remotely clear that he's an assassin? The Dark Prophecy merely mentions that Isam awaited Luc in the passes, and "One did live and one did die, but both are." There's no evidence that Slayer enters T'A'R in the flesh, considering the fact that after Perrin injures Slayer and he fades, somewhere far from Emond's Field, Slayer still ends up bolting from his room in the inn. This to me would heavily indicate that Slayer was a Dreamer of some sort.



The poison doesn't kill immediately, "They woke with small cries, but he pulled the blades free and drove them in again and again. With the poison, it was unlikely either would have had the strength to shout loudly enough to be heard outside the room, but he wanted to make this kill his own in a way that poison could not grant. Soon they stopped twitching when he thrust a blade between ribs."