彼が試験に失敗したとは驚きました。当然合格すべき男だったのです - lucifuge @Wiki

助動詞縛りは後半の「すべきだったのに」のほうか。

I was surprised to hear that he failed the examination.
He was a man who should have passed it.

さっさと模範解答へ。

I was surprised that he should have failed in the examination;
he ought to have succeeded.

む、"fail"の使いかたが・・・ちょっと考えれば、他動詞用法はおかしいことに気づくはずなのに、ああそれなのに。