I noticed we can kill the commander:
1.Start off by killing off the ranged Imps
2. Get to the 2nd floor early preferably before the 2 cambion shows up.
3. Get to a position where you can attack them (luckily necrotic hand works)
4. Snipe from atop
5. Do not return to heal, somehow I always die when I return back to the chamber
Based on my experience, if they start climbing the stairs they will probably get you.
Commander Zhalk gives 0 exp and drops a greatsword at death.
Cambions give 50 exp each and drops a greatsword at death.
Baldur’s Gate 3 Steam Guide: https://steamcommunity.com/sharedfiles/filedetails/?id=2256187516
Source
are your graphics settings turned down to prevent loading issues?
Did you know you can jump through textures with triple jump into starting location after killing cambions? 😀