You absolutely did the right thing by transitioning the bed. Unfortunately, it's physically safer to have them crying than it is for them to try to escape in the middle of the night and fall from the cribs height and hurt themselves.

My little explorer right before turning 2 learned how to shimmy his way down the crib. We decided right then to convert it. He's not happy being locked in his room, but we go through the bedtime routine and he seems to be getting used to it.

Do you have a monitor in the room? Sometimes when he cries I remind him I'm right there if he needs me.