Opening the dishwasher during mid cycle is not gonna harm the dishwasher at all.
When you open the dishwasher the dishwasher immediately stops spraying water or filling up with water so you shouldn't get any water or soap into the room by doing so.
I've opened my dishwasher mid cycle a few times because I forgot to add a few dishes to it and it never has been a problem.
It's best to let the dishwasher go on through the wash cycle if you really don't need to open the dishwasher mid cycle but it's not gonna harm your dishwasher at all to open it and stop the dishwasher mid cycle.
Or if you begin washing dishes in the dish washer and need to leave the house to do something and need to stop the dish washer mid cycle and finish the wash cycle later then that's okay too.
I never leave my dishwasher running while gone just in case it decides to continue to fill up with water and then flood the house which happened one time with my old dishwasher while I was home.
So when I leave the house or go to sleep the dishwasher is either shut off or I wait until the dishwasher completes it's cycle and shuts off.