Zombies are scientist?!?!

[Nycticorax]

Guides you same way as red did? Or do you mean why did she help you?

I mean Why did she help us. But for the sake of clarification, notice first that two questions must be disentangled:
(1) Is Swanson alive by the time you reach the Research Lab?
(2) Is Swanson infected by the time you reach the Lab?
(2) only makes sense if the answer to (1) is yes. Suppose then that (1) makes sense. Then (2) is problematic, for both answers seem to commit us to give a hard explanation:
Yes: Then why is Swanson perfectly normal and sympathetic each time she contacts you via video chat from the Research Lab?
No: Then why does Swanson attack you in the Research lab?
(2) is related to a third question:
(3) How deep are the Player mental states penetrable by Clarence?
This relationship is acute, for as a soon the creature in the Lab hits the ground, you see her as Swanson, whereas you saw her as an Infected until then. Taking this last remark onboard, let's look at the implications for (2):
Yes: Swanson is infected; you now see the creature as Swanson because Clarence is now altering your vision to make you think she wasn't and force you to feel (inappropriate) guilt.
No: Swanson is not infected; you didn't see the creature as Swanson because Clarence was altering your vision in an attempt to make you kill an innocent and now reveals the fact to enjoy your feeling of (appropriate) guilt.
With this consideration, I must say I've changed my mind. Infected cannot alter their voices and Clarence never shows to be able to alter your ear, and although Clarence never alters your seeing of dead people. And Clarence has not the power to kill you (you get killed if you don't kill the creature) at will. So I think (2) is no meaningful question.
To solve the dilemma, I then simply reject (1) above. Swanson has been killed before you reach her, and her corpse eaten out by the murderer. And the woman we see is not in any way related to Swanson, but a mere figment of imagination.