In the teaser for season 4.5 there is a shot of a bunch of Sharons giving Boomer a rubdown - oops, nope, that is not what is happening - it looks upon closer inspection that Tyrol's hammy hand is holding something and aiming for Athena-Sharon's neck as she runs and holds Hera.
And then we have Adama, bound, blindfolded and a note pinned to his chest as he is threatened with being air-locked out into space. Who would do this? He's not the Final Cylon, so it's not the humans. Do they actually kill Adama? Maybe. More likely it's yet another game of brinkmanship and Cylons reach a deal and Adama is spared - perhaps it is Roslin's ultimatum as hinted at in another teaser.