"Boys! You’ve got another one!"
I’ve always wondered why none of you, my dear Johnlock shippers, never noticed this.
Let me refresh your memory. The only room upstairs is John Watson’s bedroom (“There’s another bedroom upstairs”), and Sherlock’s bedroom is not on the third, but on the second floor, on the same level as the kitchen, in which Mrs. Hudson is depicted here.
Conclusion: It’s morning, and John and Sherlock are upstairs. Together.
I’m not a Johnlock shipper myself, but I do think you would be delighted to draw your own further conclusions on this.