Learn Italian: Il tunnel è stretto e voglio uscirne subito. - The tunnel is narrow and I want to get out of there immediately.

In this lesson, ne acts as a locative pronoun meaning "from there" or "out of it". It replaces a phrase starting with da (from). Here, it stands in for dal tunnel (from the tunnel) so you do not have to repeat the word.

Why is ne attached to the end of the verb instead of coming before it?

Because uscirne is an infinitive (a verb in its dictionary form). When a clitic pronoun pairs with an infinitive, you drop the final -e of the verb and attach the pronoun to the end: uscire + ne becomes uscirne.

Could I put the ne before voglio instead?

Yes! Because voglio is a modal verb expressing a desire (want), you have two choices for pronoun placement. Saying e ne voglio uscire subito is perfectly correct and means the exact same thing.

I thought stretto meant strict. Does it mean narrow here?

Yes, while stretto can mean "strict" or "tightly held" in some contexts, when describing a physical space like a tunnel, room, or street, it simply means "narrow" or "tight".