Her point: endings are powerful. They are the power position. All endings.
Sentence level. The last word is a powerful word. Don’t end on a word or phrase that doesn’t matter.
Paragraph level. The last sentence is a powerful sentence. Make it fierce.
Scene level. The last paragraph in a scene is a powerful paragraph. End strong, and with as much energy pointed to the next scene as possible.
Story level. The ending. Stick it. Make it blow your readers’ minds. Don’t stop writing and revising until it does.