This is quite an old phrase, dating back to WW2 at least. To "get a rocket" is to be scolded or told off, usually by someone in authority; boss, manager, teacher, parent, etc. It may go as far as dismissal.
I think Nigel made another mistake. He's going to get a rocket for that!
by New Old School January 3, 2012
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A term used when the funnist kid in the world, Joeseph White, says when he makes fun of English people in Halo 2.
"Get the Rocket Launcher", said Lindsey Phillips.
by Steven Levy December 17, 2004
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