Jim pulls out his marker (stolen from a security guard on his way in) to write Sherlock's name on the glass casing, before he shatters it (like I'll shatter HIM). As his arm swoops towards the glass to paint the familiar letters, Jim hesitates, just for a fraction of a thought - not enough to be noticed by the security cameras, he's sure of that. Can't have Sherlock see that much of himself - and recalls, in a landslide of memory, the hundreds of other times he's scrawled that name: onto walls and floors and skin and mirrors - mirrors were his favourite place to write that man's name, and he savoured the opportunities, sometimes rationing himself to only writing it once or twice, so it wouldn't get crowded, so he could admire it later. He remembers all these other times he's written that man's name, and realises he's bored of just writing it. This name isn't going to get him any closer to Sherlock by itself. So he writes it one last time, one more time, only to get that man's attention, and then he'll only settle for the real thing. Then he'll find Sherlock. Then he won't have to keep writing his name, saying his name, but only observing the man in place of having the real thing. Then the game will begin.