If your team is focused on an event's probability or likelihood, you're NOT doing SIF!
The Serious Injuries and Fatalities (SIF) model is intended to IDENTIFY events that have opportunities to cause life-altering injuries and death. And yes, most of these will (hopefully) have LOW frequencies/probabilities. So, to justify NOT responding to these LOW frequency - HIGH severity events by simply stating their likelihood is LOW is the opposite of the SIF model approach.
If you are a facility that has a PSM/RMP management system, guess what? You're already utilizing the SIF model, as both PSM and RMP are safety management systems designed to manage LOW frequency — HIGH severity events. Using the same management system tools will drive the same improvements outside of the PSM/RMP Battery Limits.