Earnest Hemingway purportedly said, "It is easy to write. Just sit in front of your typewriter and bleed." What he meant is that it's not easy at all. He was suggesting that to really write well, you need to give more than just a superficial effort. You need to find the most profound, meaningful parts of your story and manifest them on the page. I suspect this editor is asking you to dig deeper and take risks to reveal what is inside you, and the story. The statement is a bit unclear though, why not ask the editor to explain their intent? Good luck!