All I know is he made the summit and didn't come down that night. He went up alone.
" Who passed him the previous day?
I don't know. He may have been the last one to head down. It's not given in any story so far.
" What was his backup plan?
He had none.
"Where were the guys in his group?
Apparently no one from his camp knew he was up there, or realized he didn't come back. The story is only coming out, because the Inlis group is telling it. They are with a different outfitter. If the cheap outfitter group knew he was missing, they ignored it.
" Why didn't he carry enough Os?"
He figured 2 was enough.