I personally heard from the mouth of the Gaon HaRav Leizer Ginsburg shlita (and I am paraphrasing here, but this was the gist of it) that the way to determine if someone is a ben torah (for real) is his attitude towards bein hazmanim. Is it with a sigh(Unfortunately, it will soon be bein hazmanim, and of course I have to help my family prepare for Pesach, and so on) or is it more like, “Thank G-d, it’s almost bein hazmanim. I look forward to it all year long.”
If someone needs to be mafsik his learning to save a drowning person, he must do so – and if he doesn’t, he is a murderer without question, but the guy who did not have to be mafsik did a bigger mitzvah! It’s the same idea here.