Complex sentence: After waving Gordon off, Grigori continues fighting the hordes of enemies until he retreats into a nearby tomb, ignites a wall of fire around it and disappears laughing maniacally, suggesting that Grigori died fighting as Gordon was forced to keep going.
Split into simpler sentences: After waving Gordon off, Grigori continues fighting the hordes of enemies until he retreats into a nearby tomb, ignites a wall of fire around it and disappears laughing maniacally. Thie suggests that Grigori died fighting as Gordon was forced to keep going.