Caskett 키스 Theories Anyone???

OMG!!! I just saw the promo for the long awaited 3x13 episode and I know I'm not the only one excited about the 키스 between 성 and Beckett!! I'm dying to know what's behind it though because in an 기사 I read it said there's 더 많이 to it than passion so I was wondering if anyone has any good theories that have to do with the 키스 because I've got nothing lol. In the promo it showed them standing REALLY close and Beckett is laughing and then 성 just goes in for the 키스 so I'm thinking that she'll be thrown off guard and I'm dying to see what her reaction will be since she's still in a relationship unlike Castle! Sorry this was so long and please share any theories and/or 코멘트 about the upcoming episode! Thank you! :)