Earlier in day 8, Kirsten and one of the photographers tried to forge a creek, but the engine flooded, rendering the Jeep inoperable (it had to be towed away). Because the crew couldn't reach Sam's checkpoint, he kept going while drinking water from the creek / river and eating the food he had left. Meanwhile, Kirsten and the photographer hitchhiked into Silverton, met up with Kirsten's parents, and somehow made it to the next checkpoint.
When Sam arrived at the checkpoint, a decision had to be made. The crew couldn't find a local marathoner on such short notice to accompany Sam on the nighttime leg of day 8 (there are actually quite a few ultramarathoners in Silverton), so the two options were:
a) For Sam to tackle the trail at night by himself
b) To call it.
Although nobody doubted that Sam could physically keep going until the end, safety had to be the biggest concern. Badly fatigued (yet still determined, persistent, and able), Sam would have taken a huge risk to keep going without some assurance that the crew could make it to the next checkpoint. Further, without a running partner to help Sam navigate, staying on the trail in complete darkness would have been just too much of a risk to take.
Sam, Kirsten, etc. stayed at a hotel in Silverton last night, and will make their way to Denver today. I haven't talked to either of them personally, but received a lengthy voicemail from Kirsten that indicated everyone's fine.
Sam can be one of the most stubborn people I know. To make the decision to pull out based on reasons of safety and not Sam's capacity to endure more pain (which I assure you is high enough to make it to the end) was probably one of the toughest - yet wisest - decisions Sam's ever made. For one, I'm extremely proud of him and Kirsten to make this agonizing decision.
A quick aside - in Jon Krakauer's book Into Thin Air, he describes how even the best climbers have to turn back from their quest for the top of Mt. Everest for a variety of reasons - weather, the altitude, logistics, or even fatigue. This doesn't stop them from trying again, but their foresight to know when to stop is what allows them to try again, and succeed.
Sam will likely be the next person to post on this blog... I'm sure everyone will be glad to hear from him. For now - congratulations, Sam. You pushed yourself harder than you ever have before, and we're all extremely proud of you.