Either you are a talent or the company is quite screwed. I am
sure everyone will try to help you out, if this is the job you
really wanted.
Your current superior will tell you this : "go ahead, but if you
are caught, I will deny any prior knowledge of this."
Your new superior will also tell you : "if you are caught, I will
deny all knowledge that you are still in NS".
If it is only for a few days before ORD, it should not hurt. After
that, nobody cares.
