When she came back, Remu acted weird.
He seemed to be quite out of it.
Hina then ended up investigating it. She indeed saw him down while making some sort of medicine – he said it failed but was about to drink it when Hina stopped him. He then told her it had nothing to do with her at all – but she had to take responsibility for spoiling him drinking it. It’s not like it’s toxic or anything, it’s supposed to be some sort of relaxant, so he doesn’t get angry. He was holding on to her arm then, asking why, he said it’s cause of some sideeffect – he doesn’t want to be alone. Therefore, she has to take responsibility. After all he failed is because he couldn’t concentrate, which is her fault.