I was at 4 health with Warlock on Arena (at 6-2). The Pally opponent was at like 23 (don't remember exactly, but it was way too high for lethal this turn and certainly low enough for lethal next turn).
Opponent's board: Wobbling Runts, Leper Gnome, Hero Power token, a secret which I knew was a Sacred Trial.
My board: an 8/8 and a Faerie Dragon.
In my hand, I had a Clockwork Gnome, Ancient Brewmaster, Power Overwhelming and two irrelevant cards. So I figured that I couldn't prevent myself from losing with just those, so I tapped (at that point, I hadn't figured out if there was a way to win at all, but I decided to try it out and see what I could get) and topdecked an Annoy-o-Tron, which I played. And then I realized that there was a way to win if I played Clockwork Gnome into the Sacred Trial and it gave me something that prevented Leper Gnome from dying. It gave me the Freeze spare part.