I have 5 as well, all good until 1 of the twins (#5) learned to walk, thank goodness for those harnesses (especially since #3 was only 22 months older), otherwise we’d never get to go on walks (had to get 1 for his twin as well, she was jealous). Also had to get door alarms after a couple of escapes.
On our first cruise (DCL) with the grandparents, went to the buffet after embarkment. I sat down with some food, asked “where is C” (almost 5), my mom said “he wanted to go back to the cabin, he said he knows where it is.” I took off, sure enough he was in the cabin (and was never allowed to do that again). He was quite a daredevil but always landed on his feet.