DaveParillo answert is right to me but with a couple of exceptions.
War rooms works ok on short periods of time, or in a specific task that requires collaboration. I have had experiences where a whole project is developed in war rooms, in the mid of the project (about 2 or 3 months for a small project) the environment will create a destructive behavior, more if the project team members are seniors. Everything in excess is bad. War rooms work fine in my experience only for 1.5 to 2 months, or for critical phases or when you want to junior team members acquire more experience, requirents definition, some modeling, early stages of programming.
Other option for the question is do pair programming, where a senior staff member is assigned with a jr staff member for an specific time and target.