While Jason's face looked calm, everything else about his situation suggested otherwise. He was running as fast as he could from that weird yellow ambulance, or at least as fast as he could with these heels on. He thought about taking them off, but he doubted the pantyhose would provide any sort of protection from whatever was on the pavement of this alley.
He didn't know the how or why and those were not important to him at that moment. He just needed to get away. Once safe, then he could process the rest of this.