(less a first step, but more a first impression.  Sixth Doctor and Charley.  During the audio The Condemned)

The first thing Charley feels is relief.   Relief at that all-too familiar noise, relief that her friend isn't dead, and that he's come to rescue her. 
But that relief turns quickly to disappointment-  he's not her Doctor.   Not the one she'd expected, and definitely changed. 

He doesn't know her.   But there's only so much she can say -  that whole business about being a paradox and the web of Time.  
Her Doctor used to have a problem with amnesia.  This could be her plan,  a way to cover from revealing too much about herself or her previous adventures.   First off,  her name.  Charlotte...Smith! Simple enough. 

This Doctor doesn't trust her.  She can't blame him, but what if he gets suspicious...oh they're landing. 



There's something about him she recognizes.  He seems more...brash and bombastic compared to her Doctor. But something familiar is still there she can't quite place.  But never mind all that...they've got a murder to investigate.