Everyone agrees with Alyndra's plan to make a big noise and then ambush the guards...except for Harrison. Something nags at him as he ponders this idea, and then it hits him that, with every patrol or investigation, the guards don't enter the cell block together. One of them always stands at the door, with their signal horn in hand, ready to summon reinforcements if something were to happen.
Thinking about it further, he realizes that the guards are actually terrified of the PCs, based on the fact that every time they dealt with you as individuals, there were at LEAST three guards present...sometimes more.