he's in a pile of rubble. Intricately worked stone, when it collapses like this, causes, all sorts of chaos. And we'd expect he has a broken bone or twenty. He did just fall fifteen meters or so down (or roughly fifty feet, if you're using the illogical imperial system). Drops above three times a person's height are considered to be high-risk of major injuries. With your character being the height he is, broken bones are fairly guaranteed. There's also the potential for spinal damage and internal bleeding, but that's probably more up to you to figure out.

Besides, you'll steadily drain yourself of energy. Unless your character is like Kheris, which yours isn't, you won't have ridiculous stores of it. And there's an entire army around you. To the Empress, may she live forever, the soldiers are worth sacrificing. If a thousand die to remove an obstacle, it is worth it. Mind you, knowing Echo's character, that won't be preferable. 

At least we think the walls were that height mentioned above. We can't check the model now, but we did not decrease their height when we modified the model last. We may have changed it to twenty meters. We can't quite remember. If your character is 8 feet tall, and the walls are 50 feet, you fell roughly 6.25 times your own height. Not healthy.