The question for the מדרש was what did Rachel think when she saw her sister giving birth when she couldn’t, what were her concerns and how could you help her?

I think Rachel was feeling a bit sad, jealous, annoyed and a bit of angriness because she couldn’t have babies but her sister could. I would have said you should be happy for her and that you can hang out with the kids. You should go find her and tell her you are happy for her.

I think that she might have been nervous that her sister might not be ready.