Wrong? Like "bad DM" level? No.
Could it have been handled better? Yes. Giving the player reason to believe they had a reasonable chance to succeed, and playing it out as minutely as was done, when the player really didn't have much of a chance wasn't a good way to either set expectations or manage time in game.
Handling the whole sequence with a handful of die rolls would have made it a five minute prelude to the game, and communicated hte actual likelihood much better, without spending the majority of a session on it.
Pacing is a skill, and one that could have been done a bit better in this case, i think.