Pmerle00, I am so sorry for everything that you and your family are going through. I cannot even imagine the pain you must be in. It really bothers me that there appear to have been no media reports on "PaPaw"'s disappearance for the last couple of weeks. He obviously has done so much for so many over the years, and he, you and your family deserve better.
At first, after reading articles such as the ones below (all BBM):
"[Sheriff] Meeks stressed,
they found no sign of a struggle, but the blood found on the floor and on a wooden rod keep them from ruling out foul play."
http://dfw.cbslocal.com/2017/03/22/new-search-for-michael-chambers-comes-up-short/
"
Several drops of blood could be seen in Michael's shed on the property."
http://www.nbcnews.com/feature/miss...-retired-firefighter-michael-chambers-n736021
""One theory is that he injured himself inside the shop and wandered off, that's why we're conducting all these searches,' said Hunt County Sheriff Randy Meeks.
Investigators tell NBC 5 that on the day Chambers was reported missing that
a blood trail was discovered in the work shed on his Quinlan property.
'It wasn't enough blood for it to be a fatal blow. It was like if you cut your finger pretty good, and then
it looked like he walked back to the back of the shop towards the door,' Meeks said."
http://www.nbcdfw.com/news/local/Se...ighter-Getting-Close-Officials-416805783.html
I theorized, like Sheriff Meeks, that PaPaw might have injured himself, left to get help from someone -maybe a neighbor- through the door, just randomly getting some blood on the wooden rod in the process. I also assumed that there was a continuing blood trail outside the doorway, and that perhaps the searchers were following that path. However, based on the information you have shared with us -which has been extremely helpful, by the way-, the blood trail stops inside the door (all RBBM):
"The blood was not outside the shed,
but inside - leading towards the door."
"
No blood on any doorknobs. No blood outside that I know of."
So right now, I am really stuck on the question of how PaPaw was able to leave the shed, without leaving any blood once outside. Both very long shots, but a couple of possibilities I've thought of are that maybe he grabbed a towel or a rag, or that being a former firefighter, he happened to have a tourniquet in the shop, and was able to use it to stop the bleeding at least temporarily.
But then, you have also shared with us:
"I'm still looking into the deadbolt piece.
The garage doors are a possibility for exit, but not likely given certain non-public details of the scene. (sorry, I'm as frustrated as y'all are with not being able to share info)"
"
They have multiple keys. Not 100% sure, but I think one is on her car keys as well."
"There is a concerning amount, but not a fatal amount. There is a sink,
but the blood trail leads to the door, not the bathroom."
"
NOT normal for him to lock the shop while in the shop .
...
The shop was locked when his wife came home. As was the house.
Garage door down. Vehicles all locked."
It seems to me if PaPaw had injured himself badly enough to go seek help, he wouldn't have taken the time to lock the shop. He likely would have had the garage door up if he had been working on something in there, which would mean he would have closed the garage door before leaving, too (either manually, via a switch inside the shop or with a garage door opener ... was his opener found in his vehicle? ... but all vehicles were locked, with his keys in their usual place
inside the shop).
If it turns out that the deadbolt on the door was engaged, then either PaPaw locked the deadbolt himself (though again, all of his keys were found in their usual place
inside the shop), or possibly someone with access to one of the multiple copies. Or -again, both long shots- someone engaged the deadbolt from the inside first and then either closed the garage door manually, or had access to an extra key to PaPaw's vehicle, unlocked it, used his garage door opener to close the door, and then locked the vehicle with the extra key).
Only if you can answer ...: Is there any way to open the garage door from the outside? Any evidence someone tried to? I had no idea, but according to the article below, apparently, it can be done fairly easily:
http://www.news4jax.com/community/thief-can-open-your-garage-door-in-6-seconds
I am assuming there is no outside keypad door lock.
ETA: I am so sorry this post is so long. I just wanted to make sure I had all the facts right. I'm really having a hard time understanding the logistics with regard to PaPaw's exit from the shop. There probably is a simple explanation to it that I'm missing.