Saika doesn't want people dead, though. It wants them injured by its blade! Because that impregnates other people with little babby Saikas. It's a compensation love thing. Saika preys on its carrier's feelings of love, and Anri is too emotionally crippled to be cognizant of such a thing, which is why she's stayed relatively sane. At best, Anri will just be more vocal about what she's going through.
(Saika does really like strong, people. It has a canonical crush on Shizuo. Can Yuri throw a vending machine down several blocks?)