Sean was already dead, but Gao Yi could still use the dead Sean to set a trap.
Although for Sean, revenge was a matter-of-fact thing, Gao Yi thought differently. It didn't matter who killed Sean; the person who carried out the act simply couldn't get away.
An eye for an eye, a tooth for a tooth—the main thing was swift and satisfying vengeance without regrets.
Vengeance that couldn't be exacted immediately would be a matter of long-term planning; vengeance that could be executed must be done on the same day.
Now, even if those assassins outside knew Sean was dead, and even though they thought Gao Yi was spouting nonsense, they would still have to come in after hearing what Gao Yi had said.
In warfare, one always scouts out the damage, let alone in the case of assassins. Without verifying the death of the target, their mission could never be considered complete.
So as long as that phrase was shouted, someone would surely have to come in.