Sherlock hadn't planned on interrupting anything, but after a short search about and not finding Rose where she should be, he searched the halls, followed by the kitchen where he was satisfied enough to find her (how he knew she might be there had nothing to do with his interrogating people or anything, of course).

"Rose!" He called as he burst into the kitchen, rushing towards her, assuming which one she was. "Sherlock Holmes, I believe you and I have some things to talk about."