Does Takako not know? I mean its nice for a change that Takako has done something wholesome (albeit selfish) and its so that she can give Makoto more chances to have sex with Rin but does she not realize that Lisa works in the same hospital? And does she not realize by giving her the influence of the birthmark, this "Bomb" will have more chances to explode as both Lisa and Rin frequents the Hospital?