The process itself is actually correct here. The end result is stylistically incorrect, though, as I've experienced the "old man threatening you with violence" thing myself in a queue and there's no way he'd say anything like the end result.
If you want something like an actual translation case that is close to OP's situation, here's an excerpt from Gentlemen of Fortune, a Soviet crime comedy film.
> Toчнo! Кaнaй! И пycть кaнaeт oтcюдa, a тo я eмy poгa пooтшибaю, пacть пopвy, мopгaлы выкoлю!
The raw, literal translation that would be practiced by early Soviet translators and be defeated entirely by the 1950s would go like this:
> Accurate! Out! And just let out of here, or else I will knock off his horns, jaw tear, eyes pluck!
It's actually pretty hard to translate this in a raw way, but you can try MTL to get the idea.
The context here is that an infiltrator has to LARP as a hardened criminal and tells someone trying to "press" him to get out or he'll fuck him up, but isn't exactly good at it so he has to remember some of that slang as the other guy is naturally talking like that.
The "communication goal" here, the condensed message you cannot alter or change in any way or else you'd be a bad translator, would be something like
> (suddenly remembering the word) That's right! [Get out of here!] He should get out of here, or else I'll [violently bring you down to earth], [break your face], [pluck your eyes out].
You inevitably encounter losses. There isn't a single word for getting out of here in a derogatory way, so you have to describe it. Some other equivalents are also in order. The end result is something like:
> ...Right, get outta here! He should get outta here, or else I'll break his horns off, tear his gash and pluck his winkers out!
That's how you usually do it. There's a threat of violence and a bit of uncertainty, and you're preserving that as well as you can. One word is lost, but an equivalent is still found.
> Why are you telling us this?
It's fun.