BBM for focus.
That's a huge 'if'. I am pretty confident from watching Means that it was NOT on his laptop. With no hyperbole, I can say that I have been on Zoom calls 75% of every in-office workday, for the last 5 years. When people have multiple screens or a screen that is not placed where the camera is, there are telltale signs. If you watch Means (or Lori), there was no confusion at any time of which screen to look at, nobody tried to talk into the laptop or at the laptop, nobody looked back and forth, etc (which are the telltale signs).
IMO what we saw was Lori intently focused on MM's legal pad and the notes he was writing, as a device for avoiding looking at the screen (positioned where the camera was) as much as possible.