"OK... that happened..." Light said, waking up a few meters away from the creature, not too aware of what had happened in the past minute besides her head being knocked off. Nothing seemed to be getting through to the creature, but at the same time that meant that the creature showed no signs of regeneration, so any damage that did go through might be permanent. 

Grabbing a few chemicals she had taken from the armory, Light mixed a few concoctions inside a loosely sealed canister. Putting it into her pocket space, she threw down a hole and before jumping inside told everyone to move away. Causing a hole with her new canister of chemicals to appear in front of the creature, she herself backed behind a wall, poisonous hydrogen gas exploding from the canister. And just as the creature was about to pass through a metal detector, or rather due to its rampage, cause a spark and detonate the highly explosive gas. Assuming it didn't keel over from burning lungs.