<<<The 3000 were saved because they believed
and were baptised.
He who believes
and is baptized will be saved (Mk 16:16)>>>
You seem to be suggesting that the 3000 individuals who believed would not have been saved if they were not baptized? So, if you preached the gospel and Jesus Christ to somebody, and that somebody believed, but had not had himself baptized in and by the RC church, is he not saved?
It seems you just are ignoring what you read in my discussion regarding Mk.16:16. So, I will repeat myself here.
Mark 16:16 says “He who believes and is baptized will be saved; but he who does not believe will be condemned.”
He who does not believe will not be saved but will be condemned. But he who believes, will he be saved? Yes. One who is baptized, at least in the proper sense, is taken to be a believer. He is saved not because he got baptized, but because he believes. It follows then that one who does not believe and just got himself baptized, for whatever reason, or was baptized for whatever reason other than that because he believes, will not be saved. One is not saved and will be condemned, not because he was not baptized, but because he did not believe.