Retired DC9 Driver:
I will make some inquires with a 787 pilot I know in Toronto, and see if he heard what the AC crew saw..re EVA below them. I'm sure they were looking for the other aircraft and had it on their TCAS!
The chances of a collision was near zero. The controller had been trained to think airplane-to-airplane separation and had only absorbed that into her "priority memory bank." Knowing the ATC facility I am sure they thought they had trained her better,
Alas, she was trapped by the terrain to the north of LAX, which may have been a cursory part of her training.
Damn, this is all pathetic without an NTSB incident investigation.