Read New Spring and Lord of Chaos. Moiraine scoffs at the liklihood of Lan & Bukama spying on a sister undetected, and they are both elite, highly trained warriors, used to sneaking up on Shadowspawn on their own turf. Surveillance my ass. And read what Niall says about his rules for information: "Never wait to know everything. The man who waited to know everything was still sitting in his tent when the enemy burned it over his head." Elayne has learned that a very dangerous man was inserted into her entourage using murder as a diversion, and that he reports to someone who commands the services of two black sisters. What about that scenario tells you to "wait and see" and look around some more?! This is a blatantly obvious scenario and the only way anyone can find any fault in her actions (fault I notice that no one, from a Hero of the Horn of Valere, to a Black Sister who would have seized on ANY reasoanble excuse to delay the operation, to a woman who is possibly the most experienced living member of the "Battle Ajah" could find in the mission going into it) is through hindsight. There was no way to anticipate a group no one knew was even in the city coming to the aid of Shiane's cell. If someone read Shiane's & her Black pets & Hanlon's minds, they would not have known Chesmal, Asne & co. were keeping an eye out. The Forsaken themselves didn't know what that group was up to. What was Elayne supposed to do? Allow several more Kinswomen to be murdered while waiting to see if "surveillance" would turn up any more Black sisters in the city? Elayne didn't even know if she would still hold the city for the next few days, as she was already anticipating an attack by numbers she could not match on a bribed gate in the near future! Was she supposed to take a chance on letting the very women she had been sent out of the Tower to pursue out of her hands? Even if she thought there were more Black sisters, sitting around like a little chickenshit wotmaniac was simply not an option. She had no way of knowing they might have an AoL weapon that could take channelers out in a second with no warning. If her going after the Black sisters was foolhardy, what do you call Rand going after the Forsaken when everyone had to be assuming they had access to AoL tech if anyone did?

Basically Elayne took every possible precaution, and the price she paid was cheap for what she got. Half a dozen Black sisters out of action, the traitor in her group exposed and eliminated, Adeleas avenged, a pair of high-ranking Darkfriends in custody, and for no more than a useless Brown who is a rather bad judge of character and possessed of no particular assets. It was obvious from the time Adeleas died that Vandene was on a suicide run and would not long survive uncovering her sister's killer. Elayne no more got her killed than Adeleas did.

What should she have done to prevent what happened? Bring more sis- oh wait! She didn't have anyone else? Bring the Kin? With no combat experience, they'd have been liabilities. More troops? How could soldiers of Kinswomen have stopped the Black sisters from sneaking up on them, and killing them where they stood? The only reason Vandene lived long enough to avenge her sister or Sareitha lived long enough to groan, was that they were in the field of fire with Elayne, whom the Black sisters wanted alive. Asne boasted of her weapon's capabilities - she could have killed all four sisters just as easily as she stunned them. She could have done the same to a cordon of guards, and if they had brought Birgitte & the other warders in, Birgitte would have joined the casualty lists. Absolutely NOTHING Elayne could have done could have stopped what happened aside from racking up a higher body count for the good guys, aside from arresting Chesmal & friends thanks to some magical intuition of their presence in Caemlyn.

This blaming Elayne for not being omnipotent is really tiresome, considering it flys in the face of actual proven events.