I never noticed before, but my internal monolog mispronounced “reining” as “re-ining”, and it makes the meaning much more literal and I like that, also makes “re-ining in” seem redundant

Edit: Doing some light double checking, they do not seem to be fundamentally related

Rein traces back to PIE as *ten: relating to stretching/holding And in traces back to PIE as *en: still meaning in/into/around