Problem with maps like hollow is that the waves reach the core over time and you can only do it for 1h.
In Towers of doom they need to win all 6 towers so the core gets damaged that will happen from time to time but it's not like a sudden game win/loss
With the stimpack you can easily boost the heroes to 9. Here a 100 min game.


Another hint I give you. Overflow experience in a ~38h game you will get level 20 heroes in 38h bypassing the 2.25 million cap.
If you are smurfing that 3750 Gold you get in 38h totally beats the 1600+win gold you could possibly get with quests.
So use it till blizz kicks you for being afk in training as well^^