i have a problem in this quest. as soon as me and hadvar defeat the fist group of stormcloaks, and when hadvar goes to iron-bar doors, he just stands there. i tried to talk to him, i attacked him, i killed him (not really, hes essential)... nothing works. i tried multiple saves, and i tried restarting the game...but no positive result. i desperealty need help. sorry for bad english

I had a similar problem, though in mine he got stuck a little earlier, in that little corner room just outside the barracks you come into. I found Ralof had similar problem as well.

While I couldn't figure out how to actually fix the problem, you can ignore it. If you haven't already, just finish the escape, and once you get past the bear and out into Skyrim Hadvar should appear beside you and things will continue as normal. At least that's how it worked for me!

Good luck, hope that helped!