#and the fact that hearts (gamma (or maybe rai) specifically) was not only able and willing

[cause-between-and-beyond]

Redecorate by Twenty One Pilots is, I think, kind of an overall theme song for Hearts of Giants. (At least in the current continuity we're thinking of it in.) Instead of the implied fear being about death, however, it's being seen as a monster (literal or metaphorical). The last time, with the chorus being sung twice, is Hearts begging [the evil scientist guy i swear we'll figure out details eventually] to stand down. They really, really don't want to kill. But they know some of them will--and that's what ends up happening.

And so that last repetition is, first, Hearts begging ("I don't want to go like this / At least let me clean my room"), then shooting ("I don't want to leave like this"), the shot landing, ("'Cause the last thing I want to do is"), realizing what they've done ("Make my people make decisions"), and coping with the immediate aftermath ("Wondering what to do, oh / Should they keep it on display / Or redecorate?"). The plots of evil aliens can't be foiled by just killing one dude.