Leyning Kaddish when there is a bris in shul

I was recently at a ברית מילה that took place during שחרית in a shul that observes many Ashkenaz מנהגים, such as the responsive chanting of וכרות עמו הברית. It was a Monday and I was asked to leyn, which I was honored to do. After the leyning it occurred to me to chant the חצי קדוש in a festive melody, such as is done on certain other special occasions. Was this appropriate in these circumstances?