My Friends GBBR is broken

[Theo3446]

Hey guys. You seem to know a lot about guns and reddit didn’t help at all. My friend recently got a VFC G36k GBBR, when he first shot it there was a loud af sound which he said “was like an explosion” then the nozzle broke. (I assume, he said “the plastic part in the bolt”) then the tried shooting again, saying “I shot three times in semi. Then switched over to full and then it went BOOM it vented the mag into the palm of my hand freezing his fingers together.”

Now my questions...

1) Is this a easy and or cheap repair? IÂ’m considering buying the gun off him but wonÂ’t if this repair will be costly or hard

2) Where could I get these replacement parts?

3) Will this happen again? What can I do to prevent further problems?

4) What caused him this problem?

I can awnser any other questions but I am about it go on a 6 hour flight so I can get back to you then. Thank you so much for the help!