Grillin yells loudly, in Draconic, "I know, I know, we're killing them, quit your whining!"
In common, then, he shouts, "Watch out!" and casts Glitterdust to catch the Knight and Beetle (dc 19) but not the party.
He then shouts, "Target the bug first, then the knight. Oh, and the knight is weak to silver, if you've got it!"