One could also translate it as "ah, a duty calls me away" or "ah, I have an obligation I must attend to". I use the "ah" to try to capture the tone and gesture

One could also translate it as "ah, a duty calls me away" or "ah, I have an obligation I must attend to". I use the "ah" to try to capture the tone and gestures that usually accompany "if faut que j'y aille", a sort resignation and regret. A fiction recognized by both speakers.