Marina Keegan-the urgency of the moment

I discovered the writer Marina Keegan, author of The Opposite of Loneliness published posthumously

from the poem "Nuclear Spring"
So what I'm saying is you should text me back
Because there's a precedent. Because there's an urgency
Because there's a bedtime. 
Because when the world ends I might not have my phone
    charged  and
If you don't respond soon
I won't  know if you'd wanna leave your shadow next to mine.