Should I or shouldn't I....

Today is day 21 on some Lav Orp eggs I got from another BYCer. Third try this summer. Only two made it to lockdown and today I'm only seeing a lot of movement in one and may be a little in the other. On the last hatch attempt, only two made it this far and I did the wait and see approach until day 24. They never pipped and died in the shell. I REALLY, REALLY don't want to lose this one if it has a chance.
My temp has been steady at 99 at egg level and 100-101 at the top of the incubator (Brinsea Eco) and humidity flucuated between 45 and 55% days 1-18 and I've managed to keep it between 70-75% in lockdown with a couple of drops into the mid to upper 60's. The air cell is very large, about a third of the egg and I can see the chick pushing against it as it moves, but it hasn't pipped into the air cell as of now.
I've been reading through the sticky on intervening and helping them hatch after they've pipped the shell but I can't find anything on helping them by pipping the shell for them if they aren't progressing or even if I should.
I'm just so afraid of waiting until Sunday or Monday and having it die between now and then. I know the philosophy is let nature take its course and it will hatch if it's ment to. On the other hand, if it's still moving tomorrow, day 22, but starting to slow down and not pipping internally, is there any reason not to try and help and give it a chance if it's at all possible? It will either die or it won't anyway, right?
Any words of advice or encouragement greatly appreciated. Maybe I'm just being over emotional?

 

Shoot and shinola... I waited and have a dead chick. It was alive and peeping in the shell at about 1:30 am this morning, day 23. I was so excited to finally hear peeping along with the egg moving so I left it alone. When I checked it at 4, it had died.
It was huge! It couldn't get it's head untucked to pip internally. It's yolk sac wasn't fully absorbed but I'm kicking myself for not trying to help it when it might have had a chance.

 

Thanks. I was so hopeful when it was still moving and peeping last night.
I'll be trying again.