Ye Fan did indeed successfully detonate the suitcase nuke, but he also paid a grievous price.
He managed to infiltrate the Kumogo underground biochemical research facility amid the chaos, only to discover that it was much larger than he had imagined.
Although he knew that the suitcase nuke had an enormous power, equivalent to 1,000 tons of TNT, he was still worried that if it exploded in the wrong location it wouldn't completely destroy the underground facility, so he kept sneaking to the far end before returning to the central location of the underground base.
The defense and guard force of the Kumogo underground biochemical research facility were formidable, but they had never encountered such an intense attack before. Not only was the entrance to the underground base in disarray, but even the interior was somewhat chaotic, which benefited Ye Fan.