I have fixed that disaster at least ten times. That goes back a lot of years. The amazing part of it is that after a couple disassemblies with no internal damage I started to believe it never damaged the insides. As gory as that looks the fact that the Cam broke in two places is a good sign. Sort of like the kung foo guy who sticks his head through a pile of bricks.
The most amazing thing is that I have fixed at least two like that that I didn't even have to pull the injector pump. The chain bound up the crank and stopped it before the chain got off the pump gear. The area around the pump gear is made such that it can't jump a tooth. if the link between the crank and the timer gear is intact after the jam is removed the chain can be pulled up and another hooked to it and rolled through. The only thing about this fact is that there is no way to tell where #1 is. So you just put the Cam gear on and try it. If it don't work take it off and turn it 180 degrees (actually turn the crank 360degrees).
Numerous repairs with only cam, cam stands and chain (rails and such).
Unfortunately the last two I have done didn't work so well. They both had a single leaking valve which made the head have to come off anyway. It is so easy to leak check that we will now do it before heroics.
Bosch Master, ASE Master, L1
33 years MB technician