So, the hospital goes into lockdown and everyone is where they are and they cannot get out. So we have few "mini-episodes" in this episode, showing what they are doing turning those hours.
To be honest.. none of those mini episodes were superbly striking. House's one had very deep feeling and that colorschema on that scene even made the depression even intenser. But that mini-episode served it point but there were things I am not sure..
Chase and Cameron's part of the story wasn't (in some moments) not bad either. I mean.. there were really powerful moments like when Cameron yelled she did not know.. But again, the ending somehow felt weird...
And I am not even start telling about Wilson vs 13 or Foremand and Taub..