Why wasn't Alpha insane in the last episode?

My impression was that the good imprints took control as an inversion of Echo being good except for the serial killer imprint she has to keep in control. Don't know about the spinal fluids.

I can't exactly recall how they kind of explained it, but if anda watch the season two special features, there's one where they all talk about the tunjuk at a makan malam, majlis makan malam meja, jadual atau something.