Perhaps
It’s good to ask hypothetical questions and it shows you’re considering possible scenarios. However, on this occasion I think it would be misguided NOT to descend below the tracks. Why take the risk? It will only take a few minutes to do so then you’re clear of the tracks. In reality you might get a reclearance very quickly anyway at the level you request.
I was speaking with a colleague who had an inflight shutdown and diverted while in Gander airspace. He said they came back with a clearance very quickly. Hope that helps.