[Teasing is a rather effective way to drive Watanuki's attention away from specific people or subjects. Unfortunately, it will only work until Watanuki figures out that's what Merlin has been doing. The secret is safe for now, but in the future there will be quite the reckoning from an indignant student.]

Let me look first.

[This is a change too. In the past, Watanuki has practically demanded answers as soon as he was presented with a puzzle. But over the last three-ish years he has started to actually look at magic, to search out answers on his own first. He does still have to defer to Merlin quite a bit, but he often does so only after either having a guess of his own to verify or when he has completely exhausted all other options. Watanuki has always been a good student, but it's taken time for him to go from the 'sit and listen and just take all the answers from the adult' method of schooling he had been used to and grow into the 'experiment first, seek confirmation later' method that is more appropriate for studying magic.

Adrenaline gone, and his eyes are keenly scanning the image in front of him. He starts to talk through his thoughts, giving voice to them so Merlin can see what he's thinking.]

The girl is young, and her clothes look a lot like the uniforms from the Clock Tower. So she's a student, yeah? And probably all three of them are mages. Or wait, no, the red-haired one is probably just working with the other two who are mages. I don't think mages usually become doctors, and that guy is definitely a doctor.

The third...

[He trails off there, considering.]

...I'm not sure. But I don't like him.

[It's Watanuki's intuition speaking, and he's long since learned not to ignore his intuition.]