Jimb shakes his head as you leave. Whether or not you kill any kobolds, sooner or later, you get to the back of the mine and hide in the rock. While you're attempting to either stay hidden or exit the rock—both of which have the same result, namely keeping you stuck in the rock—you overhear a woman's voice say one sentence: "Sentinel Hill will burn for what Stormwind did to us."
As soon as you can get yourself out of the rock, find out where Sentinel Hill is and warn its leader before the Hill burns. Your mission here isn't done yet. Report back to Laine with what you've learned once you can get yourself out of the rock.