Before, Yan Fei had buried another god-level expert, Tripiṭaka, underground in the United States, but Tripiṭaka, with his formidable strength, actually managed to claw his way out from underground. Therefore, Yan Fei had no confidence in resolving the issue with Duan Hongye by relying on the large explosion. Even if Duan Hongye was buried underground, it would only be for a short time. Once Duan Hongye recovered, he would be able to climb out from underground just the same. God-level experts have surpassed the limits of human imagination, and with the methods currently at Yan Fei's disposal, it was very difficult to completely kill them.
After the collapse of the tunnel, the room where Yan Fei was located also felt the huge tremors coming from underground. However, the underground laboratory was originally far away from that underground tunnel and was entirely supported by hard rock, so this slight vibration did not cause any damage to the laboratory whatsoever.