I don't get it (´・◡・｀)

http://en.wikipedia.org/wiki/Java_sparrow
So instead of 'chipchipchipchipchipchipchipchip'
It's 'torpedotorpedotorpedotorpedotorpedotorpedotorpedotorpedo'

It's dangerous to go alone take this

must be Nagato giving the narration while having a massive nosebleed.

In Japanese, the 'chirp' sound is usually written 'piiii'. Here, the destroyers are saying 'torpedo' in English, emphasis on the central 'pe' syllable. Multilingual pun.