Learn Farsi: او در موتورخانه به شدت صدمه دید. - He was severely injured in the mechanical room.

The suffix -خانه is a very common way to form location nouns in Farsi. While it literally means 'house', it is frequently used to indicate a specific room, facility, or space dedicated to whatever the root word is. Here, combining موتور (motor/engine) with -خانه creates 'mechanical room' or 'engine room'. You have likely seen this before in words like کتابخانه (library, literally 'book house') and آشپزخانه (kitchen, literally 'cook house').

What is the grammatical function of به in the phrase به شدت?

It turns the noun شدت (intensity/severity) into an adverb. Adding the preposition به (to/with) in front of certain nouns is a standard way to create adverbs of manner in Farsi. Therefore, به شدت literally translates to 'with intensity', but it functions as 'severely' or 'intensely' in this sentence.

Why does the verb صدمه دید use دید (saw) to mean 'was injured'?

صدمه دیدن is a compound verb that literally translates to 'to see damage' or 'to see injury'. Farsi often uses the verb دیدن (to see) to express experiencing or suffering a negative event, which feels like a passive voice in English. If you wanted to express the active opposite, meaning he injured someone else, you would change the auxiliary verb to زدن (to hit): صدمه زدن.

Could او in this sentence also be translated as 'she'?