There is also the risk that your manager might not believe that you did not intend to leave. The whole plan sounds fishy. I don't know if I would believe someon

There is also the risk that your manager might not believe that you did not intend to leave. The whole plan sounds fishy. I don't know if I would believe someone who told me they were only interviewing to find out their market-rate salary. So, the whole thing could end up being tantamount to giving notice anyway.