There is only one Church, the Catholic one. All other Chrstians have at some point deviated from Her.
That I, as a Baptist, am not part of the "only Church" and thus am not saved ?
This I did not say. All Christians, by virtue of their Baptism, are joined together to the one Church. Your culpability for remaining outside of the Church's official boundaries and teachings is for God to determine.
until Baptists begin speaking mass in latin, accept the pope as a vicar of Christ, and worship the mortal mother of Christ as a co-redeemer, I'm afraid so (sarcasm)