Responses

I think she's referring to the Australian flowers, since they're basically a memento of her brother. In my opinion, that's some sentimental bs right there to run into a burning house for some flowers. Maybe it's something like suicide because she felt guilty for not being able to prevent her brother's death, or she loves or likes glasses guy despite the fact he loved her brother. Either way, this part was rather cliche and unrealistic. Well, it's not like that doesn't make this manga a worthwhile read.
I thought what Hatsune saw was the fire, since she said 'What's that..?'
But when said 'brother!', then ran into the fire, I couldn't help but think that actual, maybe, her brother is alive... Ah, I'm a little confused.