heart surgery

“That boy...Wait, what happened to him? But wait...I was shot straight through the heart
with a military-grade handgun at point-blank range, wasn’t I?”
“To be precise, it didn’t go through your heart, but instead ruptured the coronary artery
coming out of it. Well, either way, you probably would have died on the spot if left alone.”
Her coronary artery—it was the largest artery in the body, connected to the heart. Its
rupture meant certain death, of course. It was no different from severing the carotid artery
with a knife.
“But then, that...”
“Hm? Well, that’s probably because of the boy’s ability to control blood flow. He was
almost like an invisible hose—he passed the blood from your torn artery from one opening
to the other, without letting a single drop go. Thanks to him, we could transport you here
without you dying, and after I connected a hastily built bypass, we headed for the surgical
room. You really should thank that boy. He was using his power all the way until you got
to the surgical room, even though he was unconscious, you see.”
“...” Yoshikawa listened, baffled.

- Toaru Majutsu no Index Volume 5, Epilogue