Little Mick was to send out the alarm, while Lefty was to follow the trail.
Let Lefty follow.

At least Larry now had a few minutes to consider some plan which should look beyond the safety of the immediate moment.

He was well-dressed, albeit somewhat wet and soiled; he had money in his pockets.

What should he do?
Yes, what should he do?
The more he considered it the more ineluctable did his situation become.

By now Gavegan had sent out his alarm; within a few moments every policeman on duty would have instructions to watch for him.