well i had been keeping them in the same tank for about a month with a couple of books keeping the lid on. I suspect the bigger of the two got out first leaving the lid open enough for the smaller one.
:Glad you got the both right away, do you know how they escaped?
::yesterday both of our corn snakes escaped from there tank, we thought they were hiding in the substrate but after removing it all we discovered they were gone!
::Lucky for us we found them in the same room, one underneath the bed in the pocket of an old backpack and the other in the closet in a shoe.