The HVT is at the end of that really long drop after the first couple of rooms. Either it'll be in the open, or take a peak in the cave to your right instead of immediately turning left to the 3rd room. Sometimes it's just standing there. Try to kill it in like 10 seconds. It flees pretty quick. I've gotten it quite a few times now. Try to also have at least 6 minutes 40 seconds left of your timer so you can get up there in the 1%. That was my fastest time and I'm sitting at a score of 3,408,914. I swear every additional second adds like 1000-1500 extra points.