The exhaust probably did damage to internal parts and cables. Also they did come out at the end, which they probably wouldn't have done if your assumptions were right. Also these burn marks don't appear simply because an engine gets too hot. They will only appear by direct heat (such as from an exhaust), or an engine fire which means they have to replace the engine which they didn't.
Also ending your post with "Hahahahaha" indicates you are over-confident which is considered very rude. Even if your post did make any sense.