Re Norwegian and the whole topic of 7700 squawks..it's worth being aware that as @whatausername says, the vast majority of emergency squawks (certainly in UK airspace) are down to medical emergencies ( and sometimes they don't end well), so you'd expect the aircraft to land normally.
Also often it's ATC that asks the crew to squawk emergency because it makes their job easier - 7700 makes the aircraft is more visible in electronic terms because it removes some radar filtering, the code hasn't been punched in by the crew because a wing is falling off 😱....