GNR - Question

On the making of Dont Cry video, shannon hoon the blind mellon singer talks of how he sang a gig with guns n roses. What I dont get is that he says stuff like "i guess i was just really nervous" and "it got the better of me that night" What happened? Did he collapse or something?

I heard he just didn't do well at the gig, but it really doesn't matter cuz he died of what most of them do, heroin. RIP