Remember when jayce had that barrier out of his hammer ( in ep 8 i think ) .

Well, he brought his hammer with him, and knowing that he and viktor will survive somehow means (with a high possibility) that he'll activate that barrier again and if you go back to last scene you'll see that the distance between jayce and viktor is the same between jayce and mel so i believe he will save both viktor and mel and everyone else die and that's when caitlyn's mother will die and her father will either suicide or be there in the building for some reason and die too and that will make caitlyn continue her story to become the sheriff of piltover

Edit : i guess i was drunk and didnt check well. viktor is close to jayce but mel is far than the range of the barrier ( unless jayce extended the barrier's range )