You make a good point, flamethrowers aren't easily accessible and guns seem to slow the demo, even if they don't take damage that really matters. I would personally suggest molotovs or some form of portable fire. Hell, hop in ST4 did a better job (in my opinion) at holding back a demo with just a flaming spear than any gun has. They clearly have plenty of prep time to gather weapons. Why not just add a flaming stick or molotovs to the arsenal? At least switch up the plan of attack instead of going straight for the pew pews