Molly didn't necessarily expect Sherlock to be so wonderfully vocal in this capacity - moaning and signing with little care. It fuels her desire even more to hear how much he's enjoying himself. By the time he's pulling her hair down from its not at her neck, she is warm and itching - her coat and clothing suddenly feeling confining in the worst way. Part of her wants him to take her right here in her entryway and the other part wants this to last. As she continues kissing him, her desires are currently battling themselves and while also trying to figure out what he wants too.

Really, they win either way.