I've just learnt the titles for Episode 5 and 6. Now these are the working titles which 95% of the time remain the same as the official ones, although with such a large time between the shooting and air date this may increase the chances of them changing, but for now these are the titles.
Episode 4.05 - The Constant (Desmond Centric)
Episode 4.06 - The Other Woman (Juliet Centric)
Source: DarkUFO
