yesterday I was playing the China Shop scenario with two players. I found myself in a strange situation: I wasn't able to attack any locust and hadn't any grenade, so the only mean to make the Berserker advance was to attack my teammate. Could I do that? I searched the rules, but found nothing saying that teammate is not a legal target for an attack and nothing saying that cogs can attack only locusts, so I attacked her (actually, the other player was my girlfriend).
Result: I attacked her (who was in cover) with the normal attack of the snub pistol: I rolled 2 wounds on my attack dice and only 1 shield on her 3 defense dice dealing her 1 damage. The Berserker advanced and during AI resolution step she advanced again, moving into my girlfriend's area and attacking her dealing 4 damage and leaving her alive but without any order card... (she was very angry at me )