Why should No.2 in 'Dance of the Dead' think that No.6 would have a bomb to put in the hospital? She may well have been simply teasing, when she told the doctor-No.40 that she would warn him if No.6 was gong to put a bomb in his lovely hospital. Where did No.2 think No.6 would get a bomb? Perhaps from those dissidents mentioned by No.12 when he was interrogating No.6 in the Boardroom in during the episode of 'The General.'
But even if it had been a bomb planted at the door of the Green Done, surely any damage would have been superficial to the building. No.2 would have been safe behind what I see as the pair of blast proof doors of his office.