I am not very familiar with Japan, my knowledge is based on animes mostly ^^""" so I am not sure if my ideas will fit, but here they are anyway:
"In the span of time we live out our lives"-maybe having scene with graves that have visible birth and death dates, like some people live 70, some 20, some 5, some 104 years. All of those are some time frames and are different, lives are too, but I have a feeling that since time is relative we all got same amount of time to live trough what we are supposed to-like meaning of life is to live.
Second idea, same lyrics-2 frames, one showing craddle or something else associated with birth and other showing grave or funeral or death. And have those two frames quickly exchaneged to add to that fleeting feeling.
P.S. Maybe also blur durring that exchange