Jack glances around, moving to place himself between the others and where the sounds seem to be coming from. It isn't exactly like splicers, but similar - enough so to put his senses on high alert. One hand tightens on his wrench, and the other raises up in a sign like he's going to snap his fingers - he doesn't yet, but he's ready to, with his skin darkened and veins glowing as if there's magma just below the surface within just that hand.

He hasn't spoken once since they set out, and he still doesn't. He's like an animal right now, too focused on his targets to interact with his companions.