when should a band stop playing?

my band is gonna do its first show soon and i was wondering when should we stop playing incase theres like crowdkilling or something. i went show not long ago and someguy started punching another guy, i guess thats not a reason to stop the show but after, the guy that got punched pushed the guy to the floor and started kicking his chest and the band still continued. i dont really wanna stop the show for everyone but i dont want people dying at our shows too, anybody got some advice on when the violnece is too much for the show to continue?