She is silent, moved. In spite of all her desire not to be. She moves to Mulder, holds him.
They break slightly and she looks up at Mulder with deep respect, admiration,
and... kisses him on the forehead. When...

...suddenly a physical intimacy we've never seen. A heat and passion that can't be denied.
The opportunity for the inevitable has presented itself.

The moment of truth has arrived. Mulder is staring at Scully as she's looking back at him. His head moves slightly toward her -- as one of his hands moves up to her neck, drawing her to him.
Where there is hesitation on her part, there is also desire. When:

SCULLY:
Ouch!!!

Scully pulls away from Mulder, RUBBING at her neck where his hand had been.