Prone: your enemies get a +10 to WS and a -10 to BS, you take a -10 to WS and a -20 to parry.
When running you take a -20 to Perception tests.
Brass Knuckles are not classified as a weapon, simply enhances unarmed damage by +2.
Standard shields only suffer from Defensive there by only a -10 to attack with them.
Flame: the Agility test to avoid being hit counts as a reaction though doesn't use one. This simply doesn't allow someone to dodge them. My reasoning for this is Blast, you don't roll to hit but where the blast originates and they only get one chance to avoid the damage, not twice as RAW seems to imply with Flame based attacks.