The following page of the Baldurs Gate 3 guide contains a walkthrough for the Rescue the Trapped Man quest. This walkthrough will help you complete the quest successfully.
- Release the trapped man;
- bring Benrin to safety;
- find Miri;
- find the dowry;
- tell Benryn where Miri is.;
- talk to Benryn.
You can find the elf at Waukeen's Rest on the first floor of the building to which you break down the door (M4;7). He's pinned down by a balk in an upstairs room. As soon as you get there, you have to hurry because the fire is spreading fast. To remove obstacles, you must successfully pass an Investigation or Strength test.
Once you get Benrin out of the building, you can talk to him. He will ask you to find his wife Miri. Her body is upstairs in the building next door. Use your Speak with Dead ability (you'll learn about how to get it from a separate page of the guide) and you'll learn about the dowry hidden in the barn.
The building is located in the depths of the complex (M4;9). You will notice a haystack in it - interact with it and a gilded chest will appear. Take its contents and return to Benrin. Tell him where his wife's body is, and he'll run there. Follow him and talk to him again to complete the quest.