Up or out - do you search for jobs in advance if you're not sure if you're gonna get promoted or cut?

Hey guys, I'm in a Director role at my firm working on M&A and Corporate Finance advisory. Our company has an up or out policy, and my up or out will be coming up next year. I'm hopeful that I'll get a promotion, but there is no certainty. And this year our firm cut a lot of people, including some pretty solid ones, and it was all without any notice - a lot of them expected promotions but got let go instead. So, I'm thinking in advance on the best course of action.

On one side, it would make sense to job hunt just to have a back-up plan in case I do get let go. But on the other side, if I don't get let go and get a promotion instead, I'll stay with my company, and it will probably ruin my chances to ever recruit with the companies I'd recruit with as a back-up plan now. I imagine if I get an offer from them, and then turn it down when I get a promotion, they probably won't consider me in the future (when I may actually get a boot at my firm). Also I may have to accept an offer and then break it, if I get an offer significantly sooner before the promotion decision.

I'd love to get thoughts from experienced professionals.

Also, if you do recommend to recruit for a back-up plan, how soon in advance before the promotion decision would you recommend to do that? And what recruiting approach would you suggest: asking people in my network, or just applications on linkedin (and maybe reach out to employees on linkedin as well for a quick call?), or applications on the sites of companies, or reaching out to headhunters? 

I hesitate reaching out to people in my network because I may have to reject the offer or break the contract if I get a promotion. I also know that applications on the companies' sites or via linkedin usually don't get traction, but I do have a solid experience at a pretty big name firm and a degree from M7. And I'm also worried that if I reach out to headhunters but end up staying with my firm, I'd ruin my relationship with them and won't be able to use them in the future.

So, I was also thinking about just waiting until the promotion decision and then recruiting if needed, but I've heard that searching for jobs while being unemployed is much more difficult.

Would love to hear your thoughts.