Broody hen left: Day 22 one egg left, no signs of a pip

[MessyJo]

My broody hen had 8 eggs. 7 have hatched (last two last night). She left the nest today and there was one egg on there no signs of a pip. I tried to put it back under her, but she moved. So I candled it and did a water test. Other than lack of movement, it looks viable. It felt a bit cool when I first picked it up and I've got it in a box now with fleece, a heating pad, rice rock, moist paper towels. I'm checking the temp with a temp gun and it's up to 95 degrees. ETA: got it up to 102 now.
My questions are:
If it got too cool from mom leaving this morning, could it die in that time?
Based on the attached pictures, what's your viability opinion?
When Mom got up, I had to clean the nesting box because she had pooped. This egg was pretty dirty, could that have impacted it?
Finally, any tips on helping it in a makeshift emergency incubator?

Also included baby fluff pics

 

[AinaWGSD]

That egg quit a while ago. If there were a viable chick in there it would be dark all the way through, you wouldn't be able to see light through it at all except at the air cell.

Here is a picture of an egg on day 18 from a BYC article about hatching eggs

 

[MessyJo]

That egg quit a while ago. If there were a viable chick in there it would be dark all the way through, you wouldn't be able to see light through it at all except at the air cell.

View attachment 3871016
Here is a picture of an egg on day 18 from a BYC article about hatching eggs

Thanks! I didn't want to accidentally toss it if it was viable.