"BE MY LAST" is actually my favorite Hikki video, although the end is extremely hard to watch for me...
it has been quite a long time i have not seen it (work work work...) so i may have forgotten important things (i will take a look at it again asap), but here is what i remember of what i understood of the video:

Hikki and the lady really knew each other (the little girls we can see during the clips are obviously Hikki and the lady when they were children) and were apparently extremely close before being separated. i would even say extremely close in a kind of 'esoteric way': the lady dreams about them and about a grown up Hikki without understanding why and Hikki follows her everywhere she goes for a reason we will only understand at the end of the video: saving the lady's life...
as the lady is able to see images of their past and present, i would say Hikki should have been able to do the same with their future. this could also be a reason for the choice for a black lady and the great contrast it creates with Hikki.

but it is TOTALLY subjective do not worry and i still have to take a look at it to be sure i have not made too big mistakes
to me "BE MY LAST" looks more like the 1rst part of a story and i really would like to know a lot more about it...