Sumire is entirely unaware of anyone walking by. For all she knows, the world has completely passed her by, and her grief is all that remains. She hears the rain, but it feels like it fills her ears so wholly that little else can penetrate it. The rain, her sister's scream - her own screams at the sight of her sister's body - the thrum of her pulse in her ears, badum badum badum, beating blood through her veins, and it should have been her blood in that street, not Kasumi's, everyone would be happier if Kasumi were still here, Sumire is nothing to be sad over, she's mediocre, she's middling at best, never the athlete or the student that Kasumi is - was - or that her parents want her to be.
The world feels lonely, desolate, and does she deserve any better? She is the cause of her sister's death, and now her parents are devastated, she's devastated, Kasumi's friends are-
Dr. Maruki says she can't blame herself, but who else is there to blame? No one else ran into the street and nearly got hit by a car, only to be protected and saved by their (slightly older) big sister. The driver didn't expect two young girls to run into the road, no one else could have stopped either of them, no one had the wherewithal to know what two teenage girls would be doing in the rain on a packed sidewalk.
It takes the sharp sound of her name to realize anyone was there and that the rain is no longer reaching her. She glances up, blinking away the tears as best as she can - and sees Goro Akechi in front of her, holding his umbrella over her. She barely knows him, has only seen him in passing when she and her sister had been on a daytime TV show at the same time as him, but he's quite popular. What does he want with her, of all people?
"Y-yes? Oh, s-sorry, were you wanting to s-sit here?" She stands, drenched, her glasses coated in raindrops. The bench is absolutely soaking, not anywhere someone would want to sit when it's raining, but she doesn't know what else he could want. Instinctively, she takes off her glasses to dry them on her shirt, but they come away simply streaked with water.
Oh, she's useless, absolutely useless.