A couple stories which stand out for me:
I finished my 4th leg and was delighted. I'd run strongly and finished well. I was done and even better, we only had two more legs to go and then we were done as a team. And everyone had run well. After I finished I walked around for a bit and then realized that there were actual bathrooms at this exchange site. I went into to dunk my head under the sink since I was hot and disgusting really.
And saw an older runner I passed being helped towards the exchange by his teammates. I'd passed him on the downhill. He was running but had a bit of a limp/hitch to his gait. That's not too unusual to see at the end of a relay. My favorite from last year was seeing a young fit looking guy running his last leg at Reach the Beach Relay and he was carrying The Stick in case of need. People are well trained and not for this type of relay and dehydration/fueling/sleep issues all play a part in how a runner will run. it's not unusual to see people struggling their last leg.
This older gentleman had fallen evidently. His team members went over to help him "run" his last leg in. Honestly I was very teary watching this. I get it. It was important to finish. After the next runner took off (would that be hard or what?!), they brought him to a shaded area with a chair and I saw a volunteer talking on her radio. Soon we could hear the aid car coming. Dehydration and heat exhaustion? Probably. Spirit? Definitely.