could ill afford

Kazuo Ishiguroの "The Unconsoled" を読んでいます。

There were certain parts of the hall I could not see no matter how much I craned forward, and I realised I would sooner or later have to go down into the auditorium itself. Then, even if I were still unable to find my parents, I could at least dig out Hoffman or Miss Stratmann and demand to know of my parents' whereabouts. Either way, I saw I could ill afford to spend further time watching proceedings from my present vantage point and, turning carefully, began to make my way out of the cupboard.

"The Unconsoled" は読んでいてイライラする話が多いのですが、上記引用個所も睡眠中に見る夢で何故か話がうまく進まずグルグル回って迷路に入ったような経験と同じ印象を感じるところです。
さて、"can/cannot afford" は良く知っていますが、"ill afford" は初めてです。　"ill"なので "cannot afford" に近い意味でしょうね。

・Cambridge English Dictionary: If you cannot afford to do something, you must not do it because it would cause serious problems for you: He can ill afford to fail any of his exams.
・Merriam-Webster: to be unable to afford : to be unable to do (something) without having problems or being seriously harmed: She bought a new car, which she could ill afford.
・Oxford English Dictionary: (usually used with can or could, especially in negative sentences and questions)
if you say that you can’t afford to do something, you mean that you should not do it because it will cause problems for you if you do: (formal) They could ill afford to lose any more staff.

やはり否定的な意味でしたね。