I'm going to put this into perspective, I lost to sevak and for some reason my fight didn't lag so I know I lost and I will stay out whatever happens unless sevak wants to go again.
Stay and finish- This is the best option in my opinion. if the issue is tps, and lag, it would only be fair if everyone fights and finishes in the lag. How many of you have been to sunkiss or a fenderfell darkroom?
Its not fun, right? So imagine someone like sunshine 1v1s 65jes or a sunkiss member at the laggy base of sunkiss, now your both freezing up, barely hitting eachother, standing still for pots to actually work. One of you dies, now the winner gets to go fight at a 10x better base, the loser will probably wonder "why couldn't our match be there?" moving it mid tourney is like a sports team changing their arena mid-season due to 1 small complaint. So how do you keep it fair? don't change it, let it keep going. prepare and improve for next time, don't just change it halfway, its just not fair for others. keep it going at talosia or restart it at mag.