There is no requirement under Polish law to have an exit visa, although it would be wise to make sure that you've got the stamp in your passport to confirm that you're legally resident until the decision is made. The Urzad Wojewodzki can do that for you if you don't have one already.
what I understood is "you're legal to stay, and you have to wait in Poland unti the decision".
No, you don't have to wait until the decision is made, but you cannot cross to another Schengen country (except possibly by air, and remaining in transit - but that depends on the airport).
If your inspector told you that you have to wait in Poland until you get your karta, then I would do exactly what they say, rather than try to mess around.
It doesn't work like that. What they mean is that you won't be allowed to re-enter Poland with the stamp in the passport, nor can you re-enter with the letter saying that the decision is being made. You need a Polish visa for that.
Think about it - it would be insane if someone couldn't leave.