The grammar answer is: no, you may not, just as you can't say, "You must not enter when you superior is not" (to mean they haven't entered yet). You can't pair "is not" with an imperative verb as if it's its own past participle.
The authorial answer is: if it's the words of a character for whom such an idiosyncratic speech style would be typical, or even character-defining, it might make sense. Just bear in mind any such effort has to inculcate an attitude in readers you're happy with them having. In this case, that attitude would be, "this person's hard to parse". Only beta readers can tell you whether this makes the character less sympathetic, but maybe it's a character for whom that's not a problem.
Note: the second paragraph was for the benefit of writers, as at the time of posting this question appeared on writing.se.