ummm... Didn't we invented a marvelous escape hatch called "aqui-hires" exactly for this situations? If you have even moderately connected investors, you should be able to get aqui-hired in a week or two, very likely sipping pina colada on a Caribbean beach to stretch out before you start the new job with giant bonus vesting schedule that beats any of your colleges. Plus you get to update your Linked-In profiles with "CEO & Founder of Fantastic Startup (Acquired by whatever)". There are no loosers in startup world anymore, AFAIK.