Scanners, d. David Cronenberg (1981)
Tense, nervous headache? You probably have a Scanner in your noggin. There's no disengaging, just disassembling. It's going to get messy but, on the plus side, your skull ache will soon be gone.
I love 70s and 80s Cronenberg very much, but I also love the work of Brian De Palma from the same period. It's worth pointing out that Bri covered this very phenomenon in his 1978 classic The Fury, blowing John Cassavates into offal using only the power of Amy Irving's mind. If you ever want a high quality exploding human double bill, you know what to do.