Question about Changing Zones

Okay, so I am currently in Act 2, went through to the Shadowlands via the Underdark. I have been to the Inn with the Harper's, killed big wing man, explored the area underneath the Inn, also explored most of the abandoned town, killed the Toll keeper, Brewer, Surgeon, etc, explored part of the Tomb/Templeand I just got to Moonrise Towers and met Ketheric. I still need to rescue the prisoners from Moonrise and go to the Temple and do the thing for the Necromancer guy.

I am somewhat interested in going to the Mountain Pass to see what I missed, but I get hesitant due to the message that asks "Are you sure before going to the next zone.

My question is if I decide to go to Mountain Pass, will it jeopardize my progress in Shadowlands. I know that certain things are time dependent and I have a feeling saving the prisoners is one of those quests. I have been pretty thorough with completing content so far and don't want to screw myself into not being able to complete any quests

Just wondering if there are any negative effects from going to Mountain Pass or potentially back to Act 1. Am I potentially screwing myself by leaving the zone? What are the potential negative effects of leaving a zone? What kind of things reset, etc?

Many thanks in advance.