Well, this isn't a flaw, the game was meant to work this way.If you are surprised, the monsters get a free round of attacks... if you surprise the monsters then YOU get a free attack! What goes for the monsters goes for you, that's only fair, besides, what challenge is it if there is no risk of your party ever dying?
This is just another nice touch of this great classic, I remember my teenager stomach churching in 1981 when my party was getting surprised by the demons and starting to see my characters drop and I would QUICKLY HIT RESET !!! I often had to revert to a disk copy because I had lost my characters.
Also, Andrew and Robert thought the game out... if you characters died then you could search for them in the maze and pick them back up with another party... there was even a spell to help you out in this regard.
Snafaru