Karl gets his crowbar wedged into the mortar well enough but when he goes to maneuver the crowbar just another fraction of an inch into the hole to lever the stone upward all the better, the darned flagstone chips off. While there's now a hole large enough to peer into for Karl, he wasn't able to budge the stone. Just inside the hole, however, Karl catches sight of the creature making the cry for help. An elven woman is bound and gagged inside a shallow dugout at the bottom of the pit. Leaving off trying to delicately wedge the flagstone floor and make a "proper" job of it, Karl gets down and shoves the crowbar into the hole and heaves. Straining at the job, in time Karl shoves the heavy stone aside far enough to be able to pull the woman out, but she'll probably suffer a few scrapes in the process.
From up top, it looks like Karl could use some help. He wasn't able to pull the stone out enough to simply lift up the elf inside, so someone to either help him shove the stone aside more or to help him pull out the elf would do. Karl can do it by himself, of course, but it'll take more time.
Korgrave nudges Grotz. "Here, give me the end of the rope you've got. I'll hold it for you if you want to go down in there to help him."