No problem opening the door. Temp fluctustions don't seem to.bother the dragon eggs as long as it's withing a safe range (don't take your eggs outside where it's 30 degrees).
At first it is good to watch them and to have an idea how long they will take to hatch. After 4 or 5 clutches you will have an idea how long it takes with your set up and there will be less reason.
Make sure there is a lid on you egg container to trap humidity and.insulate against temp fluctuations (don't forget air holes of course)
90% of the time when the egg dehydrates, if you resupplying water in the form of moistening the incubation medium you can expect no issues whatsoever (with the egg, remember there is a developing embryo inside the egg).
It does happen, it is unfortunate.
It is not suggested to spray the egg directly. Putting a bit of Luke warm water in each corner of the contained should suffice. I.also suggest looking into better incubation mediums or add extra to the container to hold.more.moisture. Taking the lid off 10 times every day will dry it out fast