Why didn't No.6 try and escape during Hammer Into Anvil, It’s Your Funeral and A Change of Mind?
Well taking Hammer Into Anvil first, how was an escape possible in this episode? Escape was not on No.6's mind, nor to try and bring down the system from within, as some fans of the series think, but solely concerning himself with bringing down the sadistic No.2, in revenge for driving poor No.73 to commit suicide! There was no possible chance of escape during this episode, however there might have been half a chance at the end of It’s Your Funeral.
The assassination/execution plot of It’s Your Funeral might have given No.6 the chance to escape, after all he had managed to get the explosive detonator away from the Watchmaker-No.50. The explosive hidden in the "Seal of Office" was still hanging around the new No.2's neck, a perfect opportunity you might think. But ask yourself this, if No.6 was to do a runner to the waiting helicopter, with the explosive detonator in his grasp, who would No.6 be able to trust in stopping the new No.2 from removing the "Seal of Office" from about his shoulders in the way No.6 had for the escaping - outgoing - No.2? There was only one person, the retiring No.2, but how effective he would have been against the new No.2 is doubtful.
And as for any possible escape during A Change of Mind is also questionable, even at the end after bringing down another No.2, with the help of No.86 who denounced No.2 for being an unmutual! And don't forget, even as No.2 was being chased back to the Green Dome by certain citizens of the community after being denounced as an unmutual, No.2 would have gained the security of his office within the Green Dome, to resume control over the village and its community. If only until his replacement arrived, making any escape impossible for No.6. And even if No.2 had been chased down by the ladies of the appeals sub-committee and taken off for "Instant Social Conversion" at the hospital, there was always the Supervisor in the control room to look after things until a new No.2 arrived in the village. Just look to the week of Once Upon A Time for such evidence.