Up until now, the reader might have assumed that Sear and Core instructed Bowden to murder Mahalia once she found out the truth about Orciny to make sure no one found out about their crimes. However, as Croft pointed out as he flew away on the helicopter, Sear and Core are extremely powerful and have nothing to fear from an individual PhD student. The reality is that Bowden killed her due to his own egoism, anger, and shame.