I disagree with the new translation. It's technically correct, but it doesn't seem to have any connection to her previous statement or the commentary. "しっかり" colloquially means "get it together", but I don't think that's how she's using it, as it literally just means "firmly", "tightly", etc. もっと means "even more", and that's apparently just been dropped completely.

It really seems like she's saying rabbits are more tightly-knit as a result of the fact that loneliness is deadly to them. This accurately connects her statement to the commentary, which is a conversation she has with Reisen over the fact that she's drifting closer to Junko (and away from Tewi).