SPOILER ALERT: This interview contains major spoilers from “Only the Strong Survive,” the Season 22 premiere of “Grey’s Anatomy.” Death strikes at Grey Sloan Memorial Hospital once again.  In May, after she decided to blow up the hospital’s OR floor again in the final moments of the Season 21 finale, “Grey’s Anatomy” showrunner Meg Marinis said that every character — other than protagonist Meredith Grey (Ellen Pompeo) and Ben Warren (Jason Winston George) — could potentially be on the chopping