I'd state that injecting Kami with poison would be rather hard - even dazed he is quite capable of dodging attacks, and you'd need a serious blow to punch through his armour. The armour I put together for him is stronger than most modern tank armour, and could stop rounds from every handheld weapon known to man. 

But hey, Magnus IS an Oldblood, and Kami DID get hit by a bike, so I'll let it slide....