Pops is correct here.
some thoughts:
1. Never sign it.
2. Only get an attorney if they fire you.
3. Never admit to anything that makes you look bad.
4. go on short term disability if you to buy time (stress related is good, they don't have to know the medical issue).
5. be cunning if necessary.
6. learn the concept of "tricking the trickster", that is, play everything cool, but know that you are dealing with snakes in suits at HR and Management. they are not your friends. So, always understand that regardless of how they want you to let your guard down. They are snakes. They don't like you. They will get rid of you at any notice. be smart and like the OP says, never sign anything that puts you in a bad light.
7. don't ever work for a public traded company in the corporate world. they are animals. predatory companies that see you as labor only, and want you to do all the work, while they collect the profits. So, I would add this: if you happen to work for one of these companies, cut as many corners as you can and don't work hard unless they are watching. just pretend you are busy at all times, but in real time, don't bust your rear end for them because they don't care about you.