Gently pry one of the closest "windows" out ...do your work...put window back....you lose slightly less heat. (and that stupid flat plastic/temp pick-up probe doesn't move all over either!! like it does with removing the top) I used a "window" to reach into my bator most of the time to do stuff. And opening up a bator isn't the end of the world....momma chickens get off of the nest in rather cold weather sometimes for 10-15 minutes or more.. At 3 days into incubating I would certainly make sure the temps were 99.5-ish really close.. or swinging from 99 to 100 or there about..and NOT using the 9300 temp reading either. Use a calibrated thermometer to set the temp inside the bator with! Adjust in tenth's of a degree unless there's a LARGE problem. After opening the bator up..do not mess with the temp setting again... let it rip for at least 4-5 hours to let it stabilize again. You shouldn't have to mess with the temp setting after it's 99.5 stable UNTIL you add water at lock-down...and even then let it run for 4-6 hours before messing with it. Add 100 deg water when needing more humidity.
The eggs are probably ok...at only 3 days into incubating...probably if they are only 94 degrees at mid-egg height...but need to be mid-99's as soon as possible..
And don't fret the stock temp or humidity reading from the control panel.. They "have" been known to lead ya astray!.. get an accurate thermomenter...check it with ice water test... the PP thermometers are usually fairly accurate I have found.. but check it anyway,, And the 9300 silly flat clear piece of plastic with the temp pick-up fastened to it is a pain... but if ya wanna keep the flat plastic on...put the temp pickup end right under the controller area.. not under the heater/fan. Lay it flat on top of the eggs or close as ya can with the pickup under the flat plastic so it's "egg high"..
I finally got tired of the stupid plastic crap and quickly took the wire/probe off and taped it on a golf ball with about 1 inch of the end free hanging in the air at egg height. It worked just great..tilted with the eggs...and DID NOT slide over/off/or anywhere except where I put it. Later when the eggs were hatching it stayed PUT very well too with the little idjuts climbing all over it and pecking it even. I removed a window..pulled the temp pickup out.. removed the pain-in-tushy flat plastic...taped the wire pick-up (end of wire/probe dangling free out from the golf ball about 1 inch) to an golf ball quickly and stuck it back in an empty slot under the controller.. worked far better!