Pierce the Veil - The Balcony Scene Lyrics Meaning

I think it's kind of an interpretation of Romeo and Juliet in which one of them purposes that they both should commit suicide so they can "live" their love without impediment.

At the beggining, when it says "Don't react when I tell you..." it could be what Romeo says to Juliet before telling her his plan because he doesn't want her to think he's crazy or stop him in middle of the plan's explanation and neither wants her to shout of the shock while listening cause then someone could listen, went there and found him in her room.
In the part of "Can we lose our minds and call it love for the last time?" he would be emphasizing that what he is purposing is crazy, but still it's the only way out.
"Then no one would know the sound of a ghost" could probably refer to the fact that no one could tore them apart nor destroy their love if they are dead.
Finally, the part of "Have you ever really danced on the edge?" can be refered to the metaphoric edge between life and death and how she hasn't any need to be scared of dying because they will be together as we can see in "Just hold my hand and jump"

It's just my interpretation and idk if it will be correct but I hope it has served you someway.