It wasn't that the Solitary Eagle was afraid of getting hurt; unless the Blue Master himself casted out this skill, the Solitary Eagle wouldn't be in any danger of getting hurt.
The gap between the Solitary Eagle and Hai Chenfeng was so huge that this 'The wave of the World' maneuver simply couldn't close it down. Let alone dying, the Solitary Eagle wasn't even likely to get hurt by this attack!
However, the Solitary Eagle was still afraid of this attack coming into play even though he was in no danger of getting hurt...
[It's all over now! All the fun that I could have had is now over; I could've learnt so much more from this fight, but now this guy has inadvertently forced it all to an end... but what will I tell Meng Hong Chen when he comes looking for answers? That I forced his disciple to his death while conducting my training? That I've become a murderer? ]