Kirsty managed to do a feat thought impossible. Finally escaping Pinhead and his Cenobites for good, thanks to switching places with her cheating douchebag husband and his friends/whores. After all the years of being tormented by memories of the hell Pinhead has raised and hurting her life, she is finally at peace.
A deleted scene expands on the verbal confrontation between Pinhead and Kirsty in Hell, and even referrs back to the events of the first two films. Seeing Ashley Lawrence and Doug Bradley together on screen for the first time since Hellbound is a treat for fans.
Pinhead: It seems I've underestimated you. You've become quite the adversary.