Because you were sent by the other guard, the two at the front let you in with no hassle. Although, they do exchange a look when they see the amount of weapons Yrsa and Leilara are carrying. They direct you to Tarl, but remain at their posts.
The inside of the building is warm with body heat, and there is a general air of urgency. The former slaves all seem to be doing their part in the revolt, even the children helping move supplies. A large half-orc is in the center of what used to a meat packaging counter, listening to the report of a slender looking slave. It's safe to assume this is Tarl, and you catch the end of the conversation as you approach him.
"-- digging tunnels, but I don't know how long it'll take."
The conversation abruptly halts as you approach, both of the former slaves eyeing you warily.
"This is unexpected, who sent you? Why have you come to me?"
Tarl looks like a well-built half-orc who has seen more than his fair share of hard labor. He has many scars on his hands and back, and his left wrist is still bound by a manacle. Most of the other slaves removed theirs, but maybe Tarl has been so busy leading the revolt he hasn't found the time to remove his own yet.