Should I toss it?

I have a broody Colombian Wy. that has been setting on 11 eggs. This is a first time experience for both of us! Last night we were at about the 11 day mark and I decided to candle. I had candled them a few days ago, but only a few just to see if I could see anything. I just used a cheapy flashlight and saw life in the lighter brown ones. I couldn't see anything at all in the Americauna eggs, so last night I used my hubby's high power LED cap light and boy did that work slick! I candled all 11 of them and 10 of them look just like they should. So precious seeing those little biddies float around in there!

1 of the Americauna eggs did not look like the others. It was mostly clearish with a small black dot that appeared to be stuck to the inside wall of the egg. There was a sort of darkish red arch(not really a ring) on the other side of the egg(from where the dot was). I could see no veining and no big dark space(chick) like the others had.

Since this is my first time, I'm hesitant to just toss it without being certain that it is not viable. HOWEVER, after reading a horrible post of a bad egg explosion in the face, I'm not really wanting to chance having something like that happen either!!!

Does it sound like a dead egg to you?