Certainly an interesting bike, though it probably wouldn't be comfortably "carry-able" by someone below 5'9.

At 5'7, carrying a Brompton by the saddle is already near the limit for me without having to uncomfortably bend my arms. It doesn't look like there's many other places to wrap one's hand around other than its saddle. I can't imagine it'd be fun carrying that up a flight of stairs if you're not too tall.