This draws from the SAD SONG MV. There are a few things that I see as a reference to their movie (theatrical storyline) in this MV & wanted to list it here.

In the lyrics they reference dancing to a MAD SONG. Is this a subtle callback to the ALCOR Virus because it causes people to be filled with hatred & become murderous ?

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A few things the SAD SONG MV point out is there are instances where Keeho is disappearing & reappearing. Keeho' green hair in this MV also is a callback I believe, to the debut MV for "SIREN". 

Jiung also is seen sporting a ring that glows blue at the end causing the fire alarms to go off.

I believe this to be references to their powers. Keeho is stated calling his ability as "Controlling SPACE-TIME", better associated with teleportation. Jiung' ability is telekinesis. 

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Theo is seen in two separate shots that blend together. One with him sitting in a chair with a blue popsicle, the other version of him aiming to fire a crossbow. Theo in the chair isn't phased by a arrow going past his head in the slightest. The arrow reads as follows: "Sun is alone, but still shines." His name Taeyang, I believe means sun.

I have to say Theo with a crossbow or any weapon that you can aim is a callback in my opinion. It references his "intuition" also known as his precise accuracy. Is this why Theo in the chair isn't phased ? His aim is 100% accurate, so why would he miss the Theo in the chair ?

Theo' red hair may also be a callback to their "Doom Du Doom" MV. He is also seen alongside them members firing weapons in the "Doom Du Doom" MV

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Intak is seen in most of the MV completely beaten up. Other members are sporting scars, but it is not nearly as dramatic as Intak'.  He is covered in bruises & what appears to be dried blood, but looks to not have any real wounds. This would be on track with his ability of hyper durability. 

There is a shot within SAD SONG MV where Jongseob seemingly punched the camera, transitioning to Intak hitting the floor seemingly after being punched and coins fall out. This may be a reference to their "Doom Du Doom" MV where this happens to Intak as well.

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Jongseob' ability is never outright called, but I believe it to be omni-fabrication. Which basically is the ability to invent or create anything from desired items, to devices, & even weapons. 

There is a shot in the SAD SONG MV where he seems to pick up & hold the camera with the others behind him. Because of his ability I don't find it odd he is the one holding the camera as it mimics his fascination with the ALCOR drones from the movie, specifically with wanting to take them apart & understand their technology. Even going as far as making a ALCOR drone a pet !

There is a shot within SAD SONG MV where Intak hits the floor seeming after being punched with coins falling out, seemingly transitioned from Jongseob hitting the camera.

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Soul is seen alone in a shot surrounded by flowers & a motorbike. The flowers in front of him read: "I'm Lost". This shot is significant as from the lore of the movie, Soul is somehow immune from the ALCOR Virus & somehow in futuristic Seoul.

This may further be referenced by the solo Alien keychain. Soul is a "alien" within this as he doesn't know why he is immune. No one knows relatively anything about Soul.