I noticed that too.
Smoke everywhere, along with bodies lying around with body parts, people in deep shock, their hearing shot, wounded, moaning—and this idiot is running around shouting,
“Allah is great!” over-and-over.
Bombers showing up at their enemies’ funerals is fairly common in the ME. My guess is that either:
1) The “Allah Akbar” guy is an accomplice of the bomber, or maybe “bomber #2”, sent in case #1 didn’t succeed in his mission.
2) Some Muslims are simply death and martyrdom worshippers, and this guy is a prime example.
3) All of the above.