快刀斩乱麻
[词典] cut a tangled skein of jute with a sharp knife -- make a lightning decision; a swift and ruthless action; cut the [a] (Gordian) knot; slice through a knot with a sharp knife; cut the Gordian knot;
[例句]你应该快刀斩乱麻,把他们统统解雇。
You should cut the knot by firing them all.