[Here he just wanted to honestly, genuinely!! reassure her why this couldn't possibly be his idea, and this is what he gets for his good intentions.]
For a certain value of "common". You are familiar by now, I would guess, with this world's penchant for forcing intimacy of various kinds upon us. This tends to show up around Christmastime.
My condolences, Detective - calling for anyone else to aid us [like, say, a certain common acquaintance of theirs] will do no good now, I fear.