@JeremyECrawford, this don't feel right. Where am I going wrong? Guard isn't surprised by an attack that never happens? #dnd pic.twitter.com/y0QSUc2auC
— Jacob D (@Jacobonaut) September 25, 2016
@Jacobonaut A player doesn't get to restart combat because it didn't start in the way desired.
— Jeremy Crawford (@JeremyECrawford) September 25, 2016
As already mentioned on twitter the guard is supprised and cannot act on the supprise round REGARDLESS of his initiative.
So combat goes
1. Assasin attacks ( supprise round )
—- round ends —
2. Guard’s Turn
3. Assasin’s Turn
—- round ends —
repeat 2-3 ad nauseam