Lucifer does everything for a reason. Every word is calculated. Every blink is planned. Every shift of movement is sketched out in his mind, a world designed around him.
So when the words come out of his mouth, Gabriel knows immediately that they mean something and a moment afterwards, what they mean.
When the blade presses through him, he notes that the blade doesn't twist as it should to kill him. It's his second hint of what to do.
"Don't forget little brother, you learned all your tricks from me."
"Yes Luci, tricks. A trick that you taught me before, a trick that I used earlier tonight," he thinks.
And then it happens and it's perfect. It looks even more real than when Kali killed him before. It's got the wings and the lights and for a second Lucifer thinks that he's actually killed his baby brother.
But then a tootsie roll hits him on the back of the head and Luci snickers as he picks it up off the ground.
He senses that Gabe is gone and he breathes a sigh of relief. Gabe is safe. Gabe is okay. Gabe is gonna be fake dead until this is all over.
For a mere second, Lucifer is truly happy. Because the little brother that he raised, that he loved, that he taught everything to and promised to protect is going to be absolutely fine.
But then Lucifer thinks of Michael and how Gabe is gonna have to stop hiding after a while and come back and see who died. He's gonna have to see which of his big brothers is dead and mourn them.
And he does something he hasn't done in a long time. He prays to his Father that Gabe won't have to see one of his brothers dead and that he doesn't have to kill Michael.
And a few months later, when he's tumbling into the cage beside Sam and Adam and Michael, he smiles.
Dad still cares. Dad still loves. Dad still answers his prayers. Someday Dad will get him out of this cage and everything will be perfect again.
And with that realization, this time the cage isn't quite as bad.