Given how frantic Elon seems to be right now, I'd doubt that he would even notice if you were slacking off or just BSing. If Twitter has employees that now just snitch on the others to inform Elon, then it's already dead as all trust is gone.

If I were in the position, I'd sign the pledge (after reading it for legal gotchca's) and just try to get another job as my full time job. What's the worst that's gonna happen? You'll get fired again?