Why not purchase Sura's freedom?
So once Spartacus found out that Sura was being brought to Batiatus as a slave why not approach Batiatus about purchasing her freedom instead of planning the escape? Before he found out that Sura would be a slave as well Spartacus seemed perfectly fine with remaining a gladiator. Had he went to Batiatus about purchasing her freedom and expressed his gratitude and desire to stay on fight for him Batiatus might not have killed Sura.
I know the real answer is for drama and so there would be a show I just wished it would have been addressed in the show as an option.