When defusing a bomb, why can’t you just cut all wires at once?

Question

When defusing a bomb, why can’t you just cut all wires at once?

In: 3949

Answer 1

Follow up question; when a bomb has a primer (like a blasting cap or something) in the main explosives, why not just remove the primer instead of cutting wires? (Like when there’s blocks of c4 with that primer thing in there…)