There was no way for Kyoya to just calmly sit and wait for the healing to be done. The healing of his wife is also not trained at all, only small wounds could be healed in an instant. There is naturally more to healing than just passing down the healing energy.
Xaya was not really thinking about these things at all, believing that with the book of techniques from her master she would be able to heal her husband no matter what. That is naturally wrong.
The best method is to guide the healing power directly to the wound. In order to do that, the healer has to see through the wound; it's depth, how much has been lost, and what kind of technique had been used to inflict it. There were a lot of aspects that had to be taken into consideration!
