I think it's here worded as a simply warning, as a short form synonymous to “or else”:

or else
• used to warn what will happen if something is not carried out: you go along with this or else you're going to jail.

^{(New Oxford American Dictionary)}

I think it's here worded as a simple warning, as a short form synonymous to “or else”:

or else
• used to warn what will happen if something is not carried out: you go along with this or else you're going to jail.

^{(New Oxford American Dictionary)}