Then suddenly he stopped stock still for a split second and froze in his tracks.
He froze in his tracks for a long second before turning back to her.
He heard the cry again and froze in his tracks.
Suddenly he saw something that made him freeze in his tracks.
The last order froze everyone on the bridge in their tracks.
For one moment they all stood frozen in their tracks.
Everyone close enough to hear stood similarly frozen in his tracks.
He came to her side, then froze in his tracks.
He got no further, being apparently frozen in his tracks.
He opened the second little envelope and the message froze him in his tracks.