I'm confused about the ripping sound because breaking a match off doesn't make that kind of noise. At least not in my opinion. Striking a match is what's eerie sounding.
Match seems unused but that doesn't mean she didn't try to light it but fumbled while in panic, maybe she did it to push/seed over the idea about lightning an incense and find our culprit.
Now regarding the poison, layers is our clue. Which might mean someone had an item laced and then swiped out said "layer" once she touched it. I'd venture and guess poison was outside the cup she drank:
1. Culprit sticks a very thin film outside the cup, like those used to protect from scratches on smartphone screens and laced it with poison. Notice how he delivered her cup, he grabs it around the lid when he passes it.
2. She grabs the cup with her bare hands and later the show starts.
3a. Culprit peels off said film while it is dark and sneakingly sticks it over his own phone's screen. or
3b. He swaps the whole drink while it is dark, peels protector off then sticks it over his own phone. or
3c. He swaps the whole drink while it is dark, protector film with poison still on that cup. Notice some drinks remain on their seats's cup holders, which could be surmised that one of them is Hattori's. I'd assume police would hold any items tested for poison, so it does seem weird for those cups to remain there unless they weren't tested for poison...Which means he further swapped his drink with Hattori's in the dark!
Well, maybe there was no need to use any thin film at all and cup was poisoned just like that all along but then it wouldn't explain the layers thing unless it meant this double "swap" as a layer to hide their movements. This last part happened right beside Hattori but we know he has something else in his mind right now and might not have noticed our culprit in the dark.