so actually they don't know if San's gonna die (''probably yes'' they think) so that's why they erase Eunjae's memories?
Here is my theory ,Geumsun didn't erase the memories of Eunjae because he has experienced it how devastating it can be to see the one you love can't remember anything while looking you in the eyes with 704 (i still don't know what kind of relation they had but they will surely show us in next chapters) also the other thing is when Geumsun said 'fate is not on my side, not even once' i think he will die while protecting San or 704. The fate has already been decided ,704 escaped from the place he was captivated with a bow and came to Geumsun's place,Geumsun will take the bow and will use it, while using it he most probably will get heart. All the things that happened starting from the San's family history until this point is to determine the destiny of Geumsun(it seems like Eunjae or San is the main character but no it's Geumsun) , what needs to be happen is already happened and i think Yama also knows what will happen in the end and shaped the conditions for this path that's why 'fate makes no mistakes'
omg that's a great theory there buddy
thanks pal
I can take it if geumsun dies but not san, if he dies i will burn this place to the ground.....