Waiting for the other swimmers to complete the race before leaving your lane seems like a reasonable requirement — and simple good sportsmanship.
I have to disagree with you on this.
I can see that’s a bit of a challenge, because you really can’t tell anybody but the lanes next to you. Maybe there’s a light or a flag or something. But yeah in the end the rule is pretty clear “don’t leave your lane while the heat is still going”. It sucks in this case because of the record and implications for nationals and whatever, BUT, that’s the rules man. We’ve seen plenty of other people get records and... well... stay in their lane. So there it is.
Oh please, if you had the swim of your life and shattered the record by 4 seconds, one is supposed to twiddle their thumbs?