no. I mean maybe if I leave them no other options - the investors seem REALLY pissed about the idea of me walking away with much equity at all. but don't want to put my co-founder in the situation of having to give up more equity to investors, especially at a discount, or have to spend runway.

Just tell the other investors they can buy you out, let you keep your equity, or some combination. To do otherwise seems to twist the definition of “equity.” If a founder suddenly told an investor they “couldn’t keep their equity” there’d be lawyers involved. As soon as you tell them you want cash I’m sure they’ll shut up real quick.