1. The warrant was only valid within the county. After the first doctor refused, the police took him to a hospital in another county.
2. The warrant had an expiration time on it. The warrant was no longer valid when the colonoscopy was performed.
But this won't happen because "they were just doing their job" and the medical licensing boards have long since abdicated any pretense of a code of professional conduct. (Witness the doctors sullying their credentials to peddle snake oil supplements and diet aids on late night TV).
The Hippocratic oath is the medical equivalent of swearing a judge in on a Bible - symbolically very important, but of next to no literal significance.
For example, I bet most people don't know that the Hippocratic oath says the following:
> I will not use the knife, not even on sufferers from stone, but will withdraw in favor of such men as are engaged in this work[1]
By definition, any surgeon is violating the Hippocratic oath on a daily basis.
There are codes of ethics that doctors are expected to uphold, and the principles behind the Hippocratic oath are still relevant today, but the actual Hippocratic oath is all but obsolete.
I'm sure that the alleged actions of the doctors question violated whichever code of ethics they are bound to, but we should be discussing those instead, not the Hippocratic oath - if there is any possibility of their license being revoked, those codes are the bar against which their actions will be measured.
[0] https://en.wikipedia.org/wiki/Hippocratic_oath#Modern_use_an... [1] https://en.wikipedia.org/wiki/Hippocratic_oath#English_trans...