Tarmala has been a registered psychologist since 1998 and an endorsed Forensic Psychologist since 2010. She has worked in community and custodial settings across three states conducting risk assessments and delivering group and individual interventions. She has extensive experience working with online and high-risk sexual offenders. In addition to her work in corrections, Tarmala is a former police officer and has worked as a Police Psychologist for many years, providing wellbeing support, psychological treatment, and crisis intervention services to police officers. She currently works in private practice preparing pre-sentence reports, providing forensic supervision to mental health professionals, and assessing and treating trauma in defence force members, veterans, police officers, and other emergency service workers.