Being Svengalis didn't post the specifics, I half-assumed the BLU had hate (since they're notorious for high spike damage) which probably kept him from pulling it away. Even if Sven did have hate there is still a small window of oppertunity for it to happen depending on his reaction and connection speed or if the mob trailed back to the BLU from bouncing hate, but I'd probably agree thats a rather small or neglible variable.