There are a considerable number of Energy Blocks in the cargo hold of 8384, but replenishing them takes time.
The key is that he does not intend to completely eliminate the other side; the Customs Enforcement Team members, after all, are different from Star Thieves, even if they are dispatched workers.
Whether they are permanent staff or not, they are considered government employees, representing the Imperial law enforcement, and that's the face of the Government.
If it were far away, and something happened on the Transfer Star, it might be different, but not now.
Unless he could instantly destroy the entire Blue Elf Star, ensuring the news doesn't get out.
Qu Jianlei neither has that kind of power nor the madness to do such a thing, so he cannot just kill these people indiscriminately.
The casualties caused by the explosions of the three warships can't be said to be intentional on his part; guns and cannons are indiscriminate.
