To rescue Delane
After speaking to the noblewoman for the first time, go back to visit her once a week, choosing the "Gain her trust" option each time until you've exhausted the topics of conversation. Once you've gained her trust, you'll be able to help her escape. Once this is accomplished, you'll no longer be able to do anything at the army camp, so make sure you've done everything there you wanted to do; otherwise, events will take their course and Tarish will end up leading the orc army under the twins' banner. Success![/spoiler]