The Heralds of Corruption are a huge pain to deal with. Their constant buffing of enemies makes these two battles tough as a bolter to the head. In this section of the corrupted Space Hulk there are 4 of them to wage battle along with a hoard of servitors and repair skulls and snipers all aiming for your team.
To say this is challenging is an understatement. From the hallway, break right, take out the three Heralds of Corruption. Then go left and take out the one on the other side. Then scramble your team into the long hallway to set up a kill zone for the enemies to flow into. At this point my entire team was wiped out, save Abelard who singlehandedly took out all the servitors, skulls and snipers.