This is Ianto's courage: to keep getting up and finding a way to go on.

That's it exactly. For all we can look at Ianto's actions and know they were misguided, I have to give the guy points for trying, for being determined enough to keep trying something that everyone else thought was impossible.

I really wished Jack had asked him. I wonder if afterwards, Jack remembers this moment and wishes it too.

Hmmmm. I wished Jack had asked him too, because it would have made the whole thing a lot easier for Ianto (on the other hand, there's a good chance that since Jack didn't know Ianto very well, he would have just retconned Ianto, dealt with Lisa, and to me, that feels worse than letting Ianto go through the pain and growth of losing Lisa and grieving for her).

In hindsight, Jack might pick up on it, but I bet he wouldn't. I think he'd put it all down to Ianto getting shaken up by the Weevil and wouldn't know that was the moment when Ianto nearly surrendered (could have, would have if Jack had asked) unless Ianto told him.