I am going up the left stairs to do a quick scouting trip and see if I might stumble across Gregor as well.
The way I see this, with the food situation.
Me - 1 food ration every other day
??? - 1 food ration every other day
Savage - 0 food rations
Calcutta - 0 food rations.
We would still have 9 days of travel left if everything went correct (4 up, 5 down).
2 food rations the first day - 13 left
1 on the second day - 12
1 third day - 11
1 fourth day (reach mountain top) - 10
1 fifth day - 9
1 sixth day - 8
1 seventh day - 7
2 eighth - 5
2 ninth (reach base camp) - 3
We could go both me and someone else both eat on the way down, but if we do decide to go up the mountain, the safest way to do it, would to be send up only one more person along with me, Savage, and Calcutta. The big problem would be if we found Gregor, in this case. But I would suggest that most people descend the mountain if they want to survive.
Someone correct me, if I made a mistake somewhere.