Gosh Jason, hope you recovered with minimal loss. Sorry...
I went thru almost same scenario couple of months ago due to a malfunctioning digital thermometer.
Am thinking of adding a second one of those "el-cheapo" water temp warning alarms (~$10 at Petco) to main tank, to provide secondary warning backup.
Think I will do so today.
When bad things happen to you, they happen "BIG" ---
Best wishes to you and aquarium.
Scott