You are surprised to see Karnak flying at top speed back in your direction. The raven hovers and flaps frantically in front of you. He clearly wants to let you know that something seems obviously wrong further up ahead.
Gaven suggests the party rush to Ollie and Bill.
With daggers in hand, Oloc also urges the others to rush to the aid of Ollie and Bill. "This doesn't bode well," he adds, stating the obvious.
Duran readies his bow as he moves forward with the others trying to listen to what is up ahead.
Varros accompanies the others.
The Free Company runs back toward Ollie, Bill and the captive covering the already explored ground quite rapidly. As you enter the barracks room from the east, Bill and Ollie dash into the room from the west, running for their lives.
"Grey men!" they shout. "They killed the prisoner and tried to kill..."
Before the porters can finish, you see five men in grey, wearing long, dark cloaks. Three are carrying longbows, and two have drawn swords. They all wear leather armor, and you could swear that one of them you've seen before at the Northstar Inn. He looks like the man who declined your offer of company.*
Upon seeing you, the grey men stop in their tracks.
Unconcerned, the one you seem to recognize steps forward from the pack, sword drawn. Another grey swordsman stands to his right and slightly behind, while the other three bow-armed men spread out just behind them and to the sides, in a sort of wedge formation.
*Just for reference, here are the posts from the Northstar. It's only been about 6 in-game days since your PCs saw the guy and spoke to him, so I assumed they'd recognize him fairly readily.
Also, I will work in Varros' comment about whether the party thinks they should try to hide/dispose of Mackey's corpse as soon as this encounter ends.