The Semirhage scene seems to be one of the most popular topics here, here are my two theories regarding it.
a) Semirhage was released as the DO wanted her punished, knowing what would happen. Aside from the fact that she was recently "broken" by Cadsuane and might be spilling secrets, it would not seem out of character for the DO.
b) The true power is not actually the power of the DO. The DO's prison was created from it (as has been stipulated before) and as such, it has become tainted by proximity (similar vein to filling hole with Saidin) to such a point that he can manipulate it (and hence 'control' it). Rand is so ta'veren maybe the control slipped. This may also fit with the theory that Lanfear did not 'knowingly' bore open the DO's prison, but this was only my impression from reading it.
These theories do seem kind of contradictory. If the DO didn't control, why release Semi with the collars as punishment (although there is the other reason of Cadsuane)?
Thoughts?