I believe Time Bend 2 is a requirement.
Level: Lady Boyle's Party
Requirements: Time Bend 2, Grenade.(When you load the level you are allowed to reinvest all of your runes)Method:
At the start of the level, head across a bridge, go right past a Tallboy and head into a building. Make A Save
near a large garbage bin.
Walk through the door into a hallway infested with weepers. Make sure they see you
, even if they attack. Its important they gather around you. Blink your way to the back of the hallway - wait for them to approach you in a group.
Use Time Stop, Switch to grenades and cook it up so that the fuses is more than halfway burned. Place the grenade in the crowd of weepers. Head back to the wall and when Time Bend stops the explosion will kill the group.