往上鑽 Bore Down and Bore Up Again
如今救了你，要打底下往上鑽。若是造化高，鑽著洞口兒，就出去了；若是造化低，鑽不著，還有個悶殺的日子了。」如今救了你，要打底下往上钻。若是造化高，钻着洞口儿，就出去了；若是造化低，钻不着，还有个闷杀的日子了。」
逐句解 Line by line
"Now that I am saving you, we shall have to bore up from the bottom."
The same verb, reversed. Going down was gravity; coming up is work, and the symmetry of the two clauses is the whole difficulty stated in twelve characters.
"If your luck is good, you will strike the opening and be out; "
Here 著 is zháo, the reading for hitting a mark — striking the hole rather than merely boring at it. 造化 is luck or fortune, literally the making and transforming work of heaven, used casually.
"and if your luck is poor and you do not strike it, there will yet be a day of being smothered."
The same reading again — 著 is zháo, striking the mark, and here it is negated. That reading also pulls the negative down with it: because the character now carries a rising tone rather than a falling one, 不 keeps bù instead of shifting to bú. 悶殺 is to be stifled to death, and Pilgrim delivers the possibility without softening it at all.
Pilgrim is being unusually honest here, and it is more frightening than any threat in the chapter. He does not know that he can get them out. The plan has a failure mode and he names it: suffocation, somewhere in three hundred lǐ of rock.
The two clauses are built as a matched pair — good luck against poor luck, out against smothered — and the balance is what makes the second half land. The form promises symmetry and delivers an asymmetry: one outcome is a door, the other is a grave.
It is worth noticing how little magic is on offer. Pilgrim can turn into a fly and lift a mountain, and his account of the escape is essentially about digging in the right direction and hoping. The Bottomless Cave reduces him to the same tools as anybody else.