I didn't bother looking this up before trying so when I got him down to 10% and he held there. I ended up messing up an ae re-mez and lost tank so I just faded off to re-try. The 4 adds stayed up and stayed where we fought High Infectioner(out of the caves) but the infectioner returned to his spawn loc. Got setup, split and killed the 4 adds and than re-pulled infectioner and to my surprise he didn't spawn any adds and we burned him with no stopping at 10%.