Whoa. I'm a little conflicted on how to proceed with my Harvard SOP then. I do discuss other faculty that I'd love to work with, but it is my current lab (one of them, I'm primarily based out of a different lab and spend ~25% time in this HMS lab) that is the initial reason I wanted to apply to BBS. So in my SOP, I discuss this when I'm talking about PIs that I would like to work with.
Perhaps a safe middle ground would be to discuss this PI and how I'd like to work with her, but also put some good emphasis on other PIs and laboratories for those on the committee who are potentially red-flagging people wanting to stay in labs they've been in?