Major Bummer! One doesnít hear about this type of problem very often on an AMG engine! WOW. Iím not a tech but would suspect that perhaps something wasnít properly cleaned, or perhaps something chipped off very early on. I donít know if a scratch in one cylinder will make for a failed engine, but you know that the engine will be pretty well torn down in the process of fixing the problem. You will have a better idea at that point if there are other concerns. I wouldnít be too concerned as MB tends to do an obnoxiously good job when it comes to repairs. They tend to replace parts rather than recondition anything....
Do you know what the repair shop proposes to do?
'00 ML320 "Casper"
'92 400E "Stella"