Season 1 Episode 4, Island of Youth and Season 3 Episode 11, Dreamcatcher
In Season 1, On the island, Elena and Mateo kept running to catch up to Esteban when he's turning young, when Mateo got tired from running. Elena warns him Esteban to watch out for the quicksand, while he was positive to jump it. However, he failed and ended up in quicksand. Elena helps and asks Mateo to find something to grab on to. Elena found a tree branch. Esteban doesn't want to. Mateo asks if he wants to get out. Esteban realizes he's sinking. So he grabs the branch. Elena says to grab it with two hands. Esteban throws the map to Mateo and got out of the quicksand. He only sank to his hips I think.
In Season 3, Elena runs to get Tucansquerill till she accidentally land into quicksand, asking Zuzo to help but he tells her it's her dream she forgot, so she dreams by summon wings when she sank towards her neck and flies out of it.