The thing that drives Spartacus is the knowledge of impending doom. Maybe nothing too horrible has happened yet (relatively speaking), but we know something is coming. In "Missio," Gannicus is forced to have sex with Melitta and they're clearly pained by the act. Coming after the scene in which Gannicus, Melitta, and Oenomaus are shown to be very close, you can only imagine what will happen next. Meanwhile, Batiatus, who doesn't care about what happens to the gladiators or how they are used, revels in Gannicus's future participation in the primus by having a threesome.
Aside from the main sordid mess, "Missio" doesn't have anything new. Gaia is still a proto-Ilithyia, we've already seen Batiatus put hits on people in the street, and we've already seen powerful people force Batiatus's gladiators to fight with real weapons. The end if coming near, however, with only 6 parts, so things should heat up soon.
Score: 8.8/10