To stop dead in your tracks is to halt instantly out of shock or surprise. It made him stop dead in your tracks.
The suddenness is the whole of it, since anybody who slows down did not stop dead in your tracks. A sound behind you will stop dead in your tracks anybody walking alone.
1phrasestop dead in your tracksTo halt instantly out of shock or surprise.
“The name on the door made her stop dead in your tracks.”
stop dead in your tracks is a phrase.
Practised in Idioms