As a medical examiner I can vouch from experience that his death was accidental.

作为一名法医，我可以根据经验证明他的死是意外的。

很正确的一个句子。网友断句时，为何不顾及谓语动词 vouch （证实，证明，保证）是及物的？而且可以接 that 宾语从句。

介词短语 from experience 把“动宾分隔”了。

I （主语）can vouch （谓语动词）(from experience) that his death was accidental.（宾语从句）

英语中，这样 “动宾被介词短语分隔” 现象，太常见了：

His parents try to impress on him that it is very important to be honest.

他的父母尽力让他记住诚实是很重要的。

I explained to him that I would not have to pay for my meal. 

我向他解释说我不必付饭钱。 

We must keep in mind that we are not children any more, and we should be independent. 

我们必须牢记，我们不再是孩子，我们应该独立了。