I found out, by chance, that in the upper far left there is the open area with the teleporter.
This is where your are teleported if you land down where you came from after the fight.
You can also reach this area by flying and you are automatically transformed back in human form and Azgan does not attack you.
After the conversation and the first transformation I destroy the first nest then rush there and wait to get my health back.
Then quicksave and I rush the 2nd nest and back there. Get health back, quicksave.
Then while finishing Azgan and its minions do not hesitate to got back, replenish life, strike again and so on.
Imarion.
This way is absolutely amazing. But in my case I've focused on Zagan first -> watch cutscene -> then fly to corridor up left. That's it - you don't need to kill other demons just return to Beatrice for reward. Good luck!
