Well looks like Xela has accepted the fact that she will not survive for long on the volcanic island, so she asks Nelly to eat her and leave her in her belly until she is digested. Xela would rather die and not go to waste, and not die alone. But Nelly refuses. Xela is her best friend and she would never do anything to hurt or even kill her.
After realizing Xela might not survive on the island, Nelly changed her mind and decided to stay and help. Xela felt bad about Nelly not leaving with her group, but she said she could always meet her group at the Sanctum Isles later on.
Xela instantly remembered that name, as it was her home island. Nelly was a bit confused because that island was far away and asks Xela how she ended up on the other island. Xela will explain that later on. She asks Nelly if she would giver her a lift home in her belly. She would happily giver Xela a lift but there are too many risks like her stomach digesting her, swimming too slow and predators coming after them. Xela however knows for a secret place that can bring her back to life if the Nelly dose end up digesting her.
Nelly is still not sure about it, she still thinks Xela has a better chance of survival if they wait on the volcanic island until the dinosaurs on the other island leave. But Xela still knows she won't survive long and is willing to take that chance. But will Nelly help her? Probably is the answer.