I don't entirely get it. What is "it" here? The room where you do gamma ray spectroscopy, which should have the least ambient noise (radioactivity), or the bedr

I don't entirely get it. What is "it" here? The room where you do gamma ray spectroscopy, which should have the least ambient noise (radioactivity), or the bedroom, in which case the radioactivity is probably metaphorical? Or it's intended to be a double entendre?