How did Castiel break into Lucifer's cage and not Raphael?

We know it was Castiel who broke into Lucifer's cage to release Sam's body, but has it ever been explained how he done this? Remember how Raphael intended to do the same, but to release Michael and Lucifer instead? He was an Archangel, obviously far more powerful and knowledgeable than Castiel, and yet he seemed unable to do this?

Moving, even after breaking into Lucifer's cage, I don't see how Castiel could simply walk in and grab Sam's body, when one of the two most powerful beings were in there too? Surely Michael and Lucifer could have escaped once it was open, as there's no way Castiel could evade an Archangel or subdue one (let alone two). The only other other being to have performed such a feat was Death, but him being able to do it is understandable.