帰還 きかん不能 ふのう限界 げんかい てんでしょう
kikanfunōgenka itendeshō

Noun
Desu Copula

Expresses probability in a polite manner ("probably…") of 帰還不能限界点

1. Point of no return.; Likely irreversible.

Polite
Presumptive
Conjecture