I was thinking that he was prescient, so he can tell that he's definitely going to escape somehow (probably due to outside help). In any case, I'm totally fine with him being brutally beaten down by guards after he gets out of his cell; the main point of this is to show that Jacob is very determined, and so would be very, very unlikely to just wait for someone else to come and rescue him. He'd try and at least get out of his cell first.
In other words, as long as Jacob gets out I'm happy. I don't so much care afterwards. I do in fact have a draft where he gets zapped unconscious by his cybernetics (which are currently being controlled by the prison) as soon as he kills the guards in his cell row.