"Salvation through the Church" is kind of a strange statement. At first glance, it implies that the Catholic Church at large is saying "If you're not one of us, you're doomed". But I'm under the impression that this is just a misconception. Salvation through the Church is not a line in the sand. Its actually an open door to a treasure trove.
What is the "Church" anyway? Is it a building? It can be. But its more than a building. Is it a group? Sure. The Church is a group of believers... but its even more than that. The Church is the Body of Christ. Its a body that can't be confined by stone or drywall or wood. Its a body that doesn't hide behind stained glass, social status or geographical boundaries. The Church is a living, breathing, corporeal, spiritual body here on this earth. What does that look like on a cellular level? All of us are like individual cells that work together in community. Every day the breath of God animates us so we can say "In Him we live & move & have our being"... We're so tiny on our own, but we can get things done when we work together. Perhaps salvation through the Church could be better translated as salvation through community.
How can we experience salvation in community? Jesus said He is the Way, the Truth & the Life, so why would we need anything but Him to be saved? Well, consider His approach. He came as a man to dwell among us. He could have stayed in Heaven & sent down some pyrotechnics to freak us out... He could have sent more prophets or some super scary angels or just obliterated us all together. But He chose to become one of us in order to save us. This is love- not that we loved Him first, but that He loved us. And as His Body here on earth, we are called to love others in the same way. This is community. This is salvation, through the Church. The fullness of salvation can't be experienced without it. Within the Church we have the sacraments. These are specific ways God bestows grace through faith, & they only happen in community. Within the church, there is a lineage of believers that stretches back to the beginning of time. We are descendents of God's holy people, even as we ourselves are called to be holy.
Without the Church in one's life, the effect of the sacraments is significantly weakened or lost, the heritage of faith is all but forgotten & that one is in danger of shipwreck. The Church is a navigational tool, even like a GPS. It lays out the map, the coordinates & the ways we can take to get to our destination. It speaks to us, guides us, corrects us. How does it do this? It comes from a community of data which is based on information from satellites, maps & invisible degrees such as latitude & longitude. It knows where we're at & devises a route based on known knowledge (that yet may be unknown to us). This is the Church. Thousands of years of history & God's own intervention provide invaluable resources for us along the way. We could opt to pursue salvation outside the Church as many Protestants & even some lapsed or nominal Catholics do, but they're not experiencing the fullness of faith. Its the difference between taking a museum tour with or without the audio narration or navigating new territory with or without a GPS. Salvation comes through the Church, the community of believers; even Christ's own Body. He is the Way, the Truth & the Life.