人生沒有用不到的經歷

He was sent to the ER where the doctor set up emergent ECMO to maintain his vital sign. 這句子怎麼看文法都沒啥問題，但仔細推敲句意，的確有問題！

I have an iPhone which makes my life colorful. 我有一支讓我生活變得多彩多姿的 iPhone。---which之後的子句用來形容 iPhone (形容詞子句)。

I have an iPhone, which makes my life colorful. 我有一支iPhone，它讓我的生活變得多彩多姿。---which之後的子句用來修釋 iPhone (副詞子句)，等同下面的句子：
I have an iPhone, and it makes my life colorful.

He was sent to the ER where the doctor set up emergent ECMO to maintain his vital sign. --- where 之後的子句用來形容ER (急診室)，請問：世界上有一種專為 “醫師裝設緊急葉克膜” 的急診室嗎？

He was sent to the ER, where the doctor set up emergent ECMO to maintain his vital sign. 這樣寫就對了！等同下面的句子：
He was sent to the ER, and there the doctor set up emergent ECMO to maintain his vital sign. 
一個逗點之差，有時句意變化不大，有時會造成不合邏輯的句子。