Wandering into Abyss When Exploring Ruins

I was exploring the part of ruins with many obelisks blocking the way. I found that I can pass them before they lift up with enough speed and a certain direction. I was riding a beefalo with Glossamer Saddle. Once I was trying, I crossed the border and entered the abyss. I can walk and ride in the abyss just like the solid land, but I have to use the teleport if I want to go back.