Drone motor failure simulation

Hello!
I am trying to develop a Fault Tolerant Control System for single motor failure conditions in drones. For this I need to inject motor failure in PX4-sitl. When I try to inject the failure, the failsafe gets triggered.
I want to be able to crash the drone in the simulation. Can someone help me out with the right steps to disable failsafe and introduce motor failure in PX4?
Thanks!