I gave some suggestions (and a link) above. Having your creature or a summon active can result in them being targeted first, or block an attack meant for you, etc. Leaving this until later may result in it being ok when you return, or at least you will have better armour and can deal damage faster.
In the Developer's Cut release of the game you can load the save in the Developer Mode version and hit F11 to enable god mode until this fight is over.
