IF the world is THAT restrictive in the options you can take.... it's a shitty made world by the author....
he could confront sayaka and stop her from running in the second or third attempt, or even several more things before going with the 'let kusora get assaulted' route....
stories with premise like save and load are well made if the protag are given more freedom or cornered in a despairing sense smartly like steins gate or zero kara, this one tried going the second route, but honestly got very2 poor execution...