Look at it like this: first establish the 4 terms contingency S-S-R-S (MO-A-B-C). We’re all on the same page that running from the swarm is the behavior. So plug that in MO-A-Running-C. Running away means Joel escapes the swarm (so it functions as negative reinforcement),plug that in. MO-A-running-escape. The SD is what “triggers” the behavior (based on learners history with consequences), what comes immediately before. So what lead to the behavior or running? What came immediately before Joel started running? He saw the swarm of Zombies. So the swarm would function as the SD for running and the consequence of escape. The question doesn’t provide enough info for what the exact MO is.

Let’s say Joel just ate the biggest meal of his life, he has a leg cramp, or sees there is no where to run. Those would be abolishing operations. They change the effectiveness of the reinforcement (escape). Joel in those situations may be less likely to run in the presence of the swarm.

Let’s say Joel is at the peak of his physical fitness, familiar with the area, and sees there’s a place to run. Those could be establishing operations. They change the effectiveness of the reinforcement (escape). Joel in those situations may be more likely to run in the presence of the swarm.