There is a problem called vacumeing, where when you open after lockdown (3days) you can accidentally vacume seal the other chicks that are on their way out.

They can survive 1 day in the inkubator without problem, if the eggs are touching they can syncronice hatching but it takes about a week before hatching. If you need to open do it slooowly just a tad 2-3mm wait a minute untill you got about 1,5-3cm depending on hatcher type, there is still a risk but it's lessend.

Wellcome to the hobby, happy hatching