Как по Английски будет à la volée

phrase

While in motion or progress.

Примеры использования:

Producers were able to schedule the day's olympic coverage on the fly

idiom

If you say that you would like to be a fly on the wall on an occasion, you mean that you would like to hear what will be said or see what will happen while not being noticed

Примеры использования:

I'd love to be a fly on the wall when those two get home!, a fly-on-the-wall documentary

idiom

To do something when someone is not ready for it and is not able to deal with it

Примеры использования:

I'm afraid you've caught me on the hop - i wasn't expecting you until next week.