To get to the War Room you need to cross to the south side of the Torture Chamber. You'll have to use the raft to get to the ice, then cross and use the raft on the other side to get close enough to grapple up to the doorway. Once you climb up, you'll come to a hallway with some thugs, including an armored thug. There is a security door in front of you so look for the panel on the left to hack it. Once you've gotten it down, I prefer to start this fight with a baterang just for good measure (for taunting you). Clear these guys out and head through the door.
Go around the corner, slide under the gate and then to the right of where the prisoner is being held, put explosive gel on the wall. A fight will start that is rather similar to the one you had before. In fact, it's pretty identical. If you shock the big guy, you'll get the same result. If you stun the big guy, you can get a decent number of hits in on him. Once they are cleared out, head through the wall to the right and around the back of the make shift cell. Free Freeze by hacking the panel. He will tell you to go to his suit. Go back to the torture chamber and cross to the northern side. Climb up and walk through the door at the end.
