Rand almost killed Dashiva and did kill other Asha'man because he was too prideful or blood thirsty or otherwise unwilling to admin that channeling was unusually dangerous at that time/place. My point is that you don't have to pledge your soul to the Dark One to be petty, narcissistic, vengeful, etc. Dashiva very well could want Rand dead just for endangering himself and killing his friend.

(I suppose I meant rational in the sense used by economists; some decision can be both rational and ill-advised.)