"July 24, Part 4" (七月二十四日④ Shichi-gatsu Ni-jū-yokka ④?) is the fourteenth chapter of the Toaru Kagaku no Railgun manga series.
Back to the present day, Harumi looks at an apparently unconscious Mikoto, who is buried under the rubble she created. As she turns around, Misaka jumps out from underneath the rubble to 'hug' Harumi, explaining that she doesn't have a blind spot due to her body constantly emitting electro-magnetic waves. Mikoto attacks with a 'zero distance electric shock' before Harumi can counter, which knocks Harumi out temporarily. Their minds link and suddenly Mikoto is seeing a flashback from Harumi's memories - before the flashback at the beginning of the chapter.
Gensei is telling Harumi to teach the 'child errors' (Children who were abandoned, so the university had to take them) so that specific data would be regulated. Although she initially hates the experience, partly due to the fact that she hates children, Harumi reluctantly forms a bond with them (Although Edasaki Banri in particular). Later on, after she has finished teaching, the children go into the AIM Control Room and are put into pods to be experimented on, with the children putting faith in Harumi. During the experiment, however, the children went into shock as the experiment was failing and despite the other scientists' demands for an ambulance, Gensei insists on continuing to collect the data and covers up this continuation. Gensei approaches Harumi and congratulates her, telling her that what happened was a pity, but a needed sacrifice for the development of science.Harumi is later seen looking at Banri, her head covered in blood, and she falls on her knees in shock.
Mikoto lets go of Harumi and the flashback ends. She explains that the experiment was to "control the overrunning of [an] ability" by experimenting on the AIM of espers, commenting with disdain, that the bodies were thrown away after being used. She also explains that despite asking the Tree Diagram for the cure, she was rejected every time, showing that telling the anti-skill about these experiments would be useless, due to the directors control over them. An enraged Harumi suddenly stops and screams in pain, falling unconscious as an 'embryo' (AIM Burst) floats up from her body, which then tears up the land around it.
Kazari wakes up inside the car to find the unconscious Anti-skill guards and an 'embryo' floating beneath the destroyed highway.
Adapted from? which chapter of novel
refs to previous chapters