Ask HN: Vested options with 500K strike price. What can I do?

I have been at my current company for over 4 years. When I joined, I was offered stock options with high strike price which would cost me about $500K to exercise. At that time, I was hoping that the stock price would go up by the time it vests, and a 100% gain in the stock price would net me a decent amount of money. However, after 4 years the company is still marching on at the same stock price, still in private mode with only internal investments(no outside funding). We expect to become profitable in another two years in optimistic scenario, and things may change then (outside investment / ipo etc.). Is waiting till another two years my only option ? Or is there anything else I should considering, if I want to get out and explore other opportunities? If I could get out without any loss, I want to explore a different area for a couple of years, to give more job flexibility in the future. Currently I am working in the area of my PhD with not a lot of flexibility to move around. Suggestions appreciated.