Did That Second Repetition Really Mean That It Shouldn't Be Done?

I've had intermittent back pain, but nothing I would class as this severe or intense. You felt something maybe didn't feel quite right and then you went on to do the second rep. And it turned out fine. This is where I blame pain science now. Well, I don't, but in tongue and cheek, I do. But yeah, I do think that that first rep really should have been my clue to say that second rep shouldn't be done.