[Spoon]

Get a half-dozen new HMs whose fave HM is Chris and let them choose just one HM to keep. The rest, including Helen, are instantly evicted.

[Achilles]

Destroy the house. Make the housemates spend the rest of their time in the house living in rubble and on emergency rations with no hot water, no clothes, no grooming equipment etc Isolate them from each other into small groups living in different parts of the destroyed BB house. Housemates get evicted in the middle of the night with no warning and BB staff member comes in dressed in a scary costume and abducts them. They have their eviction interview the following evening.