Your syntax was messed up then 'The Magna Later (lol) remained immobile as the fire obliterated the entranceway just four yards in front of it.' In that sentence the distance refers to the entranceway, if you wanted to suggest the fire had cut out four yards in front of the Pater something along the lines of 'The Magna Pater remained immobile even as fire billowed out and obliterated the entranceway, falling short of the Pater itself by four yards'.

Anyway, it's not massively important in a casual battle.