Derek was out for his morning run when he caught an unfamiliar scent. Human. Bitter from fear, salty from sweat--or possibly tears. It was strong enough--and fresh enough--for him to stop.
He listened, tuning out his heartbeat and focusing on the nervous pitter-patter of the human nearby.
To his left.
The human had probably already heard him arriving, and stopping, so there was no point in being stealthy. He headed towards the heartbeat and was surprised to find himself face-to-face with someone he actually recognized.