Who needs a password anyway? You've killed several aliens - you can take this guy on!
Trying to attack Furio all at once is cheating, so you'll have to help Nick some other way.
You can yell out to Nick to boost his defence - getting hit can't be good for him.
Have you tried a distraction?
Talk to Furio, and tell him that his mohawk is falling down.
You can then 'grab' Furio to put an end to this.
That's the guard taken care of - get in there and see what they're hiding!