John didn't think much of this peculiarity at the time, but it was only after a busy crowd had unintentionally pushed him out of the way (and towards the mysterious box) in order to pass did John notice a very distinct humming noise originating (somehow) from deep within.

It was then that he received a text message that snapped him out of this moment.

There's something I'd like to show you. Be at my office A.S.A.P

- Mycroft

John reluctantly decided to do as Mycroft had requested. If it were possible to avoid taking taxis, he would. Even if he had to walk several miles without his stick. He could bear the physical pain of fatigue, but he could never bear the emotional hurt of being reminded of the customs of his high-functioning sociopath.

When he eventually reached the door to Mycroft's office after many delays, he found his first memory of entering the office was almost tangible. John shook himself out of his memory, in order to focus on the matter at hand.

"I understand the police found the circumstances of my dear brother's life just prior to his 'death' as rather suspicious" Mycroft began. "It is for that reason that they searched his records on his personal devices."

John felt his heart rate increase just slightly as he anticipated the 'password talk' to occur yet again.

"Being as oblivious as they are, they took no notice of the connection between these two oddities."

John raised a questionable look, curious as to what Mycroft would divulge.

"I'd like you to send a text to Sherlock's phone right now" requested Mycroft.

John did as he was told, and sent a simple full stop as a message, yet he couldn't help but sign it with his initials, as he always did when texting Sherlock.

"Under his contacts he has a number registered as Doctor.W, notice that the text you just sent comes up as an unregistered number, as was custom for you and my brother whilst texting." Mycroft deliberately left a gap for John to speak.

"But he never saved my number, that's why we always signed our texts." explained John.

"Oh yes, I'm aware. The 'W' definitely doesn't stand for 'Watson' like the force so dully assumed."

John stood with a puzzled expression.

"The number is disconnected. I checked it out, it's an old number, given the first few digits it likely belonged to an emergency service, most likely police. It's my theory that my brother left this as a clue for you, a lead of sorts. " Mycroft finished speaking.

John knew he wouldn't be able to get straight onto a trail after discovering the news. He had very basic skills of deduction on his good days. How did Sherlock expect him to follow such a vague lead? In normal situations, Sherlock was given a basic context of a given scene in which he would unravel the threads of mystery and tie them all up in a neat bow. But the matter at hand in Sherlock's phone was going to take a while.

Mostly out of low hopes for ever finding what the unknown number had to do with anything, John decided to search the phone number into google.

Nothing of relevance came up, even after a thorough search of each webpage.

John followed this search up with another, this time searching the name "Doctor.W".

Again, nothing of relevance to anything came up. All the search gave John was the resumes of several British and American doctors.

Getting irritated, John decided to make one more search before giving up.

He typed the words "Doctor.W police phone number" and to his surprise a suggestion appeared. Under the google search for "Doctor.W police phone box" was a picture from an old webpage that looked as though it hadn't been updated since the dawn of the internet. It was titled 'Doctor Who?' accompanied with a picture resembling the old blue wooden box that John saw just a few hours prior.