"Please spare my life!" Chelsea asked calmly.
The first time her begging dealt "damage" rather than brainwashing.
I wonder what's different.
Maybe because they were in mindscape?
Mea attempting to brainwash Chelsea could be interpreted as hostility, that's why he got forced out of the dreamworld. In previous cases, the target's hostility simply vanished, perhaps in this case he got thrown out because it's his mind's projection that's being hostile while his body wasn't physically there?
Seems Chelsea is also testing the limits of her power, as long as she knows the activating conditions (her life is being targeted) then she can be as deadpan as she wants while begging for mercy.