Don't take this the wrong way, but I'm surprised you haven't had an escape before. I use the same tubs in my quarantine rack, which really isn't a rack yet. With all of the tubs I have at least 4 pieces of electric tape on them, one on each side. It's a pain to open them but they can't push the top off. Even a small snake would be able to push the top off, so you might want to secure your pin and your boa. It's always better safe than sorry.