Does anyone notice in Ep4 (1:00:00++), ANSP receiving signal code saying spy is in the dormitory?

Code:

1. "Hosu Women's University. Dormitory"

2. "I've been searched"

3. "A high risk of exposure"

4. "Hoping to go to the North as soon as possible"

1. Isn't Sooho already escape from dormitory after open house? Who sends the signal? That person must be stays in dormitory

3. A high risk of exposure? As we know since ep1, Sooho identity is well known among ANSP

4. This ep4, we can see Sooho and his comrade already plan to go back to Northern with prof Han. Why he still hope to go the North if he's the one who sends the signal?

Also in this episode, Ms Choi asked Sooho's comrade to keep watch on Sooho and kill him if there's any changes from his behaviour. In ep5, during phone call between Rim Ji Rok (NK) and Director Eun(SK),  when Ms Choi heard Sooho's been captured, she smiles.

In Bonus scene of ep5, there is secret room which only can be accessed by Ms Pi. Is she keeping a secret of spy or is she a spy by herself or something else?

Additional:

During bed scene, Dr Kang looked bit worry and concerned while listening to Mr Nam talked over phone about NK agents. In preview ep 6 also, Dr Kang's reaction when she see one of injured NK agent lying on bed which seems suspicious to me.

Summary: 

- Sooho is being scapegoat and accused as a spy according to Ms Choi's plan

- Spy is in dormitory

- Dr Kang is also probably one of NK spy

Wait, so NK and SK have a deal, where in exchange for tons of money, NK has to send in a team of spies, capture Prof Han from the opposition & send him to NK for a staged photo-op, that'll make the opposition lose the election, and the ruling party, who has made the deal, win.
Wow. That's a STUPID deal to send your son over beyond the DMZ, tbh. Papa-Soo Ho in his Mao-suit isn't such a genius, is he? -_- I cannot believe this mission required so much of guns, ammo, planning, manpower, etc, when they could have just blackmailed Han to defect over to the North

What still doesn't add up, is the Timeline. Why would Soo-Ho already have been setting up his graduate student life under Prof Han MUCH before such a deal, and the plan to execute it, was even made!
I'm still on the camp he's a genuine grad student post his NK military discharge... and he got arm-twisted into fulfilling this mission?

That's a LOT of planning. Personal planning at that, to have your son directly involved.. and not even for national glory or anything... just to bring in a harmless prof for some cash. 

I also have a feeling, they are there for another primary mission, and this is just a cover-up instead???? The stakes HAS to be bigger than just moneeeyyyyy, to have the Mao-suit guy directly involve his OWN son. Also, the defection-bit is stuck in my mind, esp since the writers/ directors keep bringing up a defector's diary, and the Mao-suit guy's lady side-kick keeps asking Soo-Ho's fellow comrades to keep a lookout for his 'possible change in ideology' and put a bullet at the back of his head if they 'smell defection'

 Apatu:

GUYS PLS CHECK THIS OUT. Omg might be one of the biggest plot twist later

https://twitter.com/kdysoo/status/1476269755476869120

I love this theory

Check this one too

https://twitter.com/Midiru1/status/1475923302111531012