Estraeah shakes her head. No, it would be too much of a risk.
Yes, she does have rope in her bag that she could theoretically use to tie herself and keep herself safe were she to fall, but the risk is too great. If she were to fall or get stuck here, there is no way to know that she would be able to get back out on her own. Checking her cellphone shows that she has no service, so unless Klaus would somehow manage to find this exact cave and know she went into it, she would likely never be found.
It is a disappointing and anticlimactic end, but Estraeah would rather life to have more adventures. She turns to leave. Instead, she runs directly into her brother, Klaus.
"Hey Estraeah," he greets casually as if they were not crossing paths in a mysterious cave. "What are you doing?
Estraeah decides to go along. "Well, I had intended to see where this cave led, but alas my exploration has been halted by the enormous gap in the floor."
"Uh, what gap?"
In disbelief, she whips around to show him the cavernous hole behind her, but when she goes to do so, it is missing.
". . . huh." Perhaps she had imagined such a drop? No, definitely not. She directly shined her flashlight down to gauge the distance to the bottom. It was there, and now it is not.
This cave is, in fact, magic. Estraeah knew it had to be.