From what I understand duels were illegal during the Revolutionary Period so the participants took great lengths at protecting witnesses from any potential legal action. But how does turning your back on the duel make you any less innocent of not being a witness? Since a doctor was paid for in advance, couldn’t the prosecution argue that they took some part in the duel?
Not to discourage further answers but /u/Georgy_K_Zhukov, resident duelling expert, addressed this exact question here, and if they're around I'm sure they could answer followups.