No scans, it's a logic thing that you failed to see. If it helps you improve, this was likely due to bias. A machine that can blow up if it gets messed up enough can very much not blow up if not messed up enough, and then blow up when damaged some more. It doesn't matter how Nova was already damaged before and that didn't blow him up as there is no proof that that damage would blow him up, but there is proof that Marx hitting him blows him up as he blew up from that. Marx hitting him being the "most important part" is meaningless value to how Marx hit him, we don't knowing how its mechanisms work and how all we can go by is the visuals are redundant info that you redirect w/o any reason to what you claimed, Nova's still a machine, machines can blow up on their own, another machine like Nova even blew up when dying after a rather slow final blow.
In other words, if receiving 10 of damage will blow you up then receiving 9 of damage will not blow you up, but any more damage after that will.