Yep they should be arrested and made to pay for the damage.
Truth be told this sort of thing even happens in the UK with unruly passengers that cause damage to planes.
Although the title is a bit far-fetched, the fact of the matter is that the conditions are now right for Biman to realistically aim to be the best airline in S Asia by 2030:
1. BD economy is really strong and predicted to stay this way till 2030 at least. Airline passenger numbers will grow 8-10% a year till then.
2. Boeing is in trouble and this is allowing a cash-strapped BD to buy 6 787s at huge discount prices. 10 787s is a good core to base a fleet around.
3. The management of the company has improved a lot over the last decade. Youtube reviews confirm that the service is now much better than it was before.
I think there is too much negativity that BD cannot improve just because it has struggled in the last. Fun fact is that FDI into BD was 4.5 billion US dollars in 2018-2019 and that is around 80% of what was achieved in the whole decade of the 2000s. If outsiders have confidence in BD that they are putting billions of US dollars into BD each year then there is no reason why BD'shis should not as well.