That could be a great place to start. Crowley could try to scare him off and then get really annoyed when it doesn't work. In turn, Eliot could try a fire attack at Crowley, and fire doesn't affect him at all. Crowley could try for a few fire attacks of his own, and maybe Eliot could deflect them back?

This could create the feeling of a standoff and give them a chance to talk. Crowley is a bastard, but he's definitely not unreasonable and doesn't want to kill anyone.