Just to nit-pick, lane 1 starts at the start/finish line, the others start “ahead”.
Official FINA rules for swimming:
SW 12.12 The first swimmer in a relay, except in mixed relays, may apply for a World Record or a World Junior Record. Should the first swimmer in a relay team complete his distance in record time in accordance with the provisions of this subsection, his performance shall not be nullified by any subsequent disqualification of his relay team for violations occurring after his distance has been completed.
SW 12.13 A swimmer in an individual event may apply for a World Record or a World Junior Records at an intermediate distance if he/she or his/her coach or manager specifically requests the referee that his performance be especially timed or if the time at the intermediate distance is recorded by Automatic Officiating Equipment. Such swimmer must complete the scheduled distance of the event to apply for a record at the intermediate distance.