Our son’s bed is one of those 3-in-1 transforming cribs that goes from traditional crib, to toddler bed to regular full size bed. We knew it was time to switch to a big kid bed the night we heard a loud THUNK followed by a screaming wail. We ran into his room to find him on the floor, unharmed, but a little frightened and most likely already plotting how to climb out without alerting us next time. The next day we were all excited to change the crib to the toddler bed, which is pretty much the same set-up, but…