I can't take credit for that quote because Midnite graciously provided it. And Roger isn't being quite as sensitive as one might suspect from his words. In fact, you're quite right that his body language belies his words because he's being more facetious than anything. But then, when it comes to his dealings with Sam, sensitive is hardly the word that comes to mind.
(And for a change Liz isn't actually stonewalling - she's mostly an observer in the scene. It's Laura (who is hidden behind Roger) who's being less than truthful.
)
Here's the quote/capture:
1967: Ep #146 - Roger: 'I'll be as delicate as possible.' And here's the excerpt from Robservations:
... I was hoping the two of you could work things out, says Maggie, but it's worse than ever. How do you mean? asks Roger. My father is convinced that Mrs. Collins started that fire. Liz looks suspiciously at Laura, Roger at Maggie, disbelieving.
That's absurd, pronounces Laura. I know it is, says Maggie, but it's stuck in his mind. How could he make such accusations? Asks Laura. There's no basis for it, agrees Maggie. I've never heard anything so insulting, I won't have him going around saying things like that, fumes Roger. I wish you could talk to him, and try to get it off his mind, says Maggie. I'll get it off his mind, Roger assures her, rising and striding for the door, have no fear. The doctor's been with him, says Maggie, and he's in a very nervous condition--the doctor says it's anxiety. I'll be as delicate as possible, says Roger, and leaves. ...