If the egg is going to hatch, it will internally pip prior to making an external pip. It may not internally pip for as many as 3 more days.
Regardless of all the do not open the incubator during lockdown warnings, it is okay to open the incubator during lockdown. Keep the openings brief and allow the temperature and humidity to stabilize between openings.
It is not an absolute requirement to raise the humidity for lockdown for a single egg. I have had keets and poults hatch in my cabinet incubator while under incubation parameters and even while the auto turner was running. I don't recommend keeping an auto turner on.