How do people who hold salvation as a one time event respond to passages of "being saved"?

Philippians 2:12 Says: >12 Therefore, my dear friends, as you have always obeyed—not only in my presence, but now much more in my absence—continue to work out your salvation with fear and trembling, 1st Corinthians 15:2 Says: >2 and by which you are being saved, if you hold fast to the word I preached to you—unless you believed in vain. There are a large sect of Christians (mainly fundamentalist evangelicals) in America who hold salvation to be a once a done, one time event. How do they respond to these passages? ----------------------------------------- Related: https://christianity.stackexchange.com/questions/57396/how-can-1-corinthians-153-be-reconciled-with-calvinism-and-limited-atonement