turn of the screw

The Quiet Americanにいかにも慣用句らしい表現が出てきました。
Expulsion meant the end of a whole life, it meant the victory of Pyle, and there, whan I returned to my hotel, waiting in my pigeon-hole, was in fact his victory, the end of the affair--a congratulatory telegram of promotion. Dante never thought up that turn of the screw for his condemned lovers.
"turn of the screw" の意味を調べます。
・Cambridge English Dictionary: an action that makes a bad situation worse, especially one that forces someone to do something: Each letter from my bank manager is another turn of the screw.
・Macmillan Dictionary: an occasion when someone puts more pressure on someone else to do something: This latest demand was one more turn of the screw on the government.
これは分かり易いので簡単に覚えられそうです。
"pigeon-hole" は動詞の "pigeonhole(3/27/2010)" / "pigeonhole(6/6/2014)" を以前採り上げたので意味は推定できますが、念のためにWiktionaryで確認します。
1.A nook in a desk for holding papers.
2.One of an array of compartments for sorting post, messages etc. at an office, or college