This pattern recurs in many literary works. When I was watching an animated movie the character said just the pattern below. I cannot tell for sure what he said but it was probably while. I thought I'd ask about which word is more common, while or when.
We should have verbed somebody (when/while) we had the chance
- We should have locked him up (when/while) we had the chance
- We should have killed you when we had the chance
Edit: After a repeated listening it turns out that the word was when! Anyway, I don't trust my ear yet. I still need your input.
Now I could think of another reason why it should be when and not while. While is mostly used, as I see it, in present, pressing situations. And when is just for an event at a point of time in the past.