Ummmm i have killed a few yeasts in my day
Also newbies ringing up at the shop re airlock not bubbling turn out to have killed the yeast. . .all this seems to show that in a well sanitised fermenter a wort will keep for a few days, plenty of time to buy another yeast.
Always, courage! Beer is very forgiving, buy another bloody yeast, pitch away and very likely a great beer will result
Jovial Monk