Fly the aircraft to a safe altitude then reduce thrust as normal. Take a breath and see whats happening.
Had an RB211 cough it's guts out during base training. It's more startling than catastrophic. Especially if the flames are shooting forward of the nose. But a surge is due to bad airflow and a change in thrust or airspeed could fix it.
So use it while you can and make it safe when you don't need it anymore.