Yeah, it's overall a fairly poorly written module. It's got cool themes and a lot of nice ideas but the execution is pretty poor across the board, this too being one of those (the idea is good, great even - but boy, the execution...). But as ever, this just means we need to optimise enough to beat poor design as players As a DM, you can actually make it pretty good - give the PCs chances to rest, have the enemy do some "Honorable villain"-stuff like leave the PC alive for a good fight (and not use breath or action surge unless the enemy pushes you enough to do it), etc. but this is of course not in the module and we're working with the module as written here.