Disclaimer: The events described below are based on radio broadcasts and notes I took on Oct 27th and 28th. All summaries of climbing events seem to spark some disagreement and/or controversy, so I will only claim that this account is as accurate as my note-taking and others' gossip.
The base camp radio crackles to life. The Chinese climbers (Zhangwei and Yadi) went for the summit last night and are not moving fast. We learn that they left Camp 1 at 10pm and reached the top at 12:30pm the next day (Oct 27th). A standard summit push leaves from Camp 2 and takes 8-10 hours up. The descent can be done easily in a few hours.
At 3:45pm another broadcast: Yadi is still above Camp 3 after three hours, normally an hour descent. Yadi's sherpa, Sona, continues to guide the exhausted climber down, as his guide, Zhangwei, takes refuge in the single tent at Camp 2.8.
70kph winds rake the ridge as night closes in. No one else is above Camp 2.
At 5:15pm, Sona reports that Yadi has made it to Camp 3 but won't come down any farther. Zhangwei tries to coax Yadi down, this time in Chinese, explaining that "there are only three more rope lengths". An average climber would be there in 15 minutes. Only silence from Yadi.
To say the atmosphere in our tent at Base Camp was depressing would be an understatement. Arnold speculated that Yadi had High Altitude Cerebral Edema (HACE), an illness that fills the space between the skull and brain with fluid, altering behavior and depressing vitals. His slowness and refusal to come down fit the diagnosis.
Rescue scenarios were discussed but ultimately decided against. Sherpas would have to ascend from Base Camp and wouldn't arrive until late the next day, far too late to make a difference. A long-line helicopter rescue would be risky at 6400m without the high winds and cover of darkness.
I'm pretty sure it was Yadi who made that comment at 6:45pm, but I know that's the moment the far-away drama became very, very real for me. Sona had left Yadi and descended to Camp 2.8. He could only assume that Yadi would die without help. After 20 hours on the move in -30C temperatures, neither climber could have had much left in the tank to muster a rescue either.
Arnold turned down the volume. A few left for the tea house to drink away the inevitable. I stayed up for another hour, but without news I headed to bed, glad I don't remember my dreams.
In the morning, I was surprised to hear that Yadi and the others had started descending from Camp 2.8 at 6am. Zhangwei had met Yadi at Camp 3 and descended with him later in the night. That night, Yadi had also thrown away the radio in a HACE-fueled delirium, but was able to move down under his own power the next day. They arrived around 7pm, uninjured, and flew to Kathmandu the following day.
My 20/20 hindsight: They got so lucky. Zhangwei's acclimatization plan was reckless with a client. Ascending to over 6800m, having never been above Camp 1 at 5600m or sleeping there until they went for the summit, Yadi was at high risk of altitude illness. Letting Yadi get so exhausted and not turning around before the summit, Zhangwei ignored the standard mountaineering axiom that "the summit is only half way". In not recognizing the symptoms of HACE and not using the medicine carried for precisely this situation, he could have killed Yadi. But I wasn't up there. I wasn't exhausted. And Zhangwei knew to get to the tent to recover, which likely saved Yadi's life.
The pall that settled over Base Camp slowly lifted as we prepared for our own chance at the mountain. We had done the right things. We were prepared. We were cautious, but nothing like that would happen to us, right?