Realizing he could use the Nascent Energy to break open his bloodline locks, he had become very excited.
Opening the first lock had increased his bloodline energy capacity by several folds, gave him a powerful Bloodline Ability (The Finger Attack), increasing his battle power by a lot.
Not only that as it also enabled him to sense his women's location no matter where they were, and gave him the Bloodline Sense… both of which were very useful in their own way.
So, how could he not be excited about unlocking the second lock, especially when he had a guess what its reward was going to be?
When he observed the seals, he managed to sense the second seal which was most likely because Nascent Energy was saturating it and making it tangible. He thought like this because he couldn't sense the upper three seals at all.
Anyway, when he observed the second seal, though very vague, he sensed something familiar.