This is so frickin easy!
As someone already pointed out ->
As soon as the "boss" bit starts, run over to the far wall (where crowe is standing up on top off shooting on) and simply lie down.
The alphas cant hurt you when your lieing down.
So all you have to do now is simply pick off the alphas with guns as soon as they appear.
This is very very very very easy.
You can have 3 or 4 unarmed alphas trying to attack you without guns right beside you and they cant scratch you.
Once all the alphas are dead, get up and shoot crowe a few times and make him jump down.
Then quite simply keep running from him and shooting then feral attack him.
Keep feral attacking him, he dies very quickly.
Piss easy!