A group of 6, university student aged male climbers, who mostly were very inexperienced and only a few routes out of Conville course planned to climb Forbes Arete from Le Tour in Chamonix. 16:00, started walking from Le Tour (1500m) and from the off I was incredibly slow compared to my group. I repeatedly asked to abort the plan and go down but my group convinced me to get to the Refuge Albert Premiere (2700m) so to see how I felt the next morning. I'm not especially unfit, just not fit enough for these people! After resting in the hut and then sleeping to 00:00, we set off again up the Glacier Du Tour (3300m). Again, I was slow but I was pushed very hard by my partner on my rope so we didn't fall behind the rest of the group. By the time we reached the rock (3500m) I was exhausted and as we continued climbing developed altitude sickness because of this. I was further denied an escape despite explaining clearly that I was not in shape to summit and literally belaying between my legs. The group realised as the sun rose that we were on the wrong Arete and that by the time we could reroute we would be too far behind schedule to get off the mountain safely. Decision was to bail down a steep snow slope preceded by a loose and steep traverse. At the bottom of the snow slope was a cravasse that we needed to jump across. Two pairs preceded us, one had cleared the cravasse and the other we crossing the cravasse as we made our way across the traverse. As I was in a bad way, I followed my leader but started slipping and ejecting loose rocks down the rockface towards the pair below. Screaming "Rock" repeatedly, and then grabbing a large rockspike that my leader had slung and clipped to our rope, I was out of control. The large rockspike dislodged and fell onto me, too large for me to hold, it slid off me and fell towards the pair below. Apparently they hid in a shelf within the cravasse so to avoid the coffin sized lump of granite crash by them. I saw the sling rip off the rock as it fell, melting the dynema as it did so and very nearly pulling myself and my partner off the face and into the cravasse below. After everyone below evacuated and I had cried a lot, I was able to decend unprotected back onto the glacier and back to the refuge. I reflected that I nearly killed myself and 3 others.