It doesn't make any sense.

可以说毫无意义
They got attacked when they went to the play, so they go to plays in

他们在看戏时遇袭之后并无大碍
order to stay safe because they happened to survive that attack.

从此就认定看戏能保证他们幸免于难
The reason why we're given that logic is that this book is full of

这整本书都是这类精神错乱的故事
stories about insanity.

于是就有了这种逻辑
And remember, from the story about Moon Orchid, insanity in this story

不知你们不是还记得在Moon Orchid里
is defined as telling one story over and over again,

精神错乱被定义为不断重复一个故事
insisting on the same story.

非得是同一个不可
She becomes paranoid, essentially a paranoid schizophrenic.

她变得愈发偏执几乎就是个精神分裂症患者
That means that sanity, healthiness, is found in

所以不管是精神错乱或还是健康它的根基
multiplicity, illogic.

都是庞杂混乱脱离逻辑的
It's a kind of contradictory claim about the status of sanity

这种神经质和情节编排