Ethos, pathos, logos and kairos are not three writers or four paragraphs — they are moves made sentence by sentence, and they overlap. Build one op-ed paragraph by choosing a version of each slot, then read the same paragraph twice: once as a nurse, once as the hospital finance officer who will actually decide. “Effective” is an incomplete word until you finish it with on whom.
Four slots, three ways each
Watch for overlap. “He lived” is pathos (relief), ethos (honesty about the outcome) and logos (the near-miss is the actual evidence) in two words. If a bar below moves alone, the slot is doing only one job — usually a sign the sentence is working too hard.