Collector edition already has digital download of the OST (https://www.beamdog.com/products/baldurs-gate-siege-of-dragonspear-collectors-edition , buttons on the left). (View Post)

If ou are referencing to this place : https://forums.beamdog.com/discussion/51431/underground-river-trapped-wall , then it is not an other entrance. The only one i know is the main guarded entrance. (View Post)

I found the quest related to this trap. It is the secret cache of the thieves guild in the coalition camp. When you confront the quest leader in the camp, you can ask for a part of their treasure, sh… (View Post)

Minor globe of invulnerability is also enough. (View Post)

https://www.beamdog.com/products/baldurs-gate-siege-of-dragonspear-collectors-edition Here is the soundtrack (on the left buttons) if you have the collector edition. (View Post)