This was because Kinuhata’s small body was blown away by a sudden shotgun blast from the side.
The girl’s slender body wrapped in a white wool dress bounced two or three times on the road. The sudden gunshot caused a panic among the surrounding onlookers, but Kinuhata kept her cool as she rolled along. The blast had spread out to cover from her right cheek to her chest, but she was not bleeding thanks to Offense Armor.
(…I only heard one gunshot but there were 20 shots. Each individual bullet is greater than 5 mm. With that, I should be able to use something in the area as a shield without having to super use my powers!!)
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The next shot did not have the usual single gunshot of a shotgun.
It was the sound of a gun on full auto.
“Wha—? That’s not a normal shotgun!?”
The car did not last as a wall for even 2 seconds.
It wasn’t just that bullet holes were created in it. Like a balloon being popped from within, the metal body tore apart. The downpour of shots that had pierced it headed straight for Kinuhata’s body. Even with her thin wall of nitrogen, the overwhelming amount of force blew her away.
She was knocked over 10 meters away.
When she got back up, she realized she had a trail of blood running down her cheek.
It wasn’t a fatal wound, but her armor had been pierced.

Toaru Majutsu no Index vol.19 ch.2 pt.11