"Gabriel Self-destruct" 

Asmodeus was with his official medium, so, the so-called restriction had the minimum effect. 

There were four demon lords fighting against Gabriel, while Gabriel only had three people on his side, including himself. 

In such a situation, Gabriel was cornered bit by bit, and the archangel realized that he might really die there. 

Realizing that no matter how hard he tried to occupy Ainsley, he would still die in the end because of the baby and the demon lord's scheme of throwing his medium behind the gate... 

Gabriel changed his purpose and tried to make it so that his death wouldn't be in vain, unlike Archangel Raphael. 

Since he couldn't escape death, anyway, how about severely injuring Ainsley and Asmodeus? 

With a weak demon lord and an even weaker medium, no matter what, Ainsley couldn't escape from the battle angels' barriers.