FPGAs are a very flexible and powerful tool to do safety research.
The main property of FPGA is their low latency. Communicaton lines within devices can be interfered and data transmitted over one line could be tampered. So one user used an FPGA to listen to the i2c communication between a micro-controller and a radio chip and rewrite certain messages sent from the micro-controller to the radio chip. This way the frequencies used by the device could be reprogrammed without the need to hack and reprogramming the control software on the micro-controller.
Explore some examples here: