There are Saints who where catechumens and who were martyred before having been able to receive water Baptism. The Holy Innocents, too, are in Heaven.
If one has access to water Baptism, but refuses to receive it, then one is condemned. If one has, moved by supernatural faith and charity, the sincere intention to receive it, but dies an unforeseen* death before the actual reception, that person receives the fruits of Baptism.
Also, when a Saint and Doctor of the Church says that a certain doctrine is de fide and that the contrary position is at least temerarious, then you can not simply dismiss it.
*Unforeseen by the said person, not by God.