Sherlock is quite the discreet and shy person, he's an omega, so, he mostly acts submissively and timidly...

He is in front of your office... It is located next to Mycroft's one because you both work in the government, taking care of confidential matters. He knocks at the door and when he hears you say "Come in!" in a strong and authoritarian voice, he comes inside... He becomes more nervous when he understands you are an alpha.

"Um... Hello... I'm Sherlock Holmes, Mycroft told me we could work together...I hope I'm not already bothering you..."