>>fnbr+(OP)
The only way I can see this being a valid contract is if the equity grant that they get to keep is a
new grant offered the time of signing the exit contract. Any vested equity given as compensation for work could not then be offered again as consideration for signing a new agreement.
Maybe the agreement is "we will accelerate vesting of your unvested equity if you sign this new agreement"? If that's the case then it doesn't sound nearly so coercive to me.