Looks like he’s wearing Islamic clothing to me.
This is AFTER the building should have been empty.
It’s fire fighter Ali Baba.
Clearer video looks like a man in a white hard hat and yellow safety vest. Not unreasonable for maintenance staff to check for issues where relatively safe.
And fire suppressing is obviously well under way. I’d expect an arsonist would be long gone by then.
He looks like Bin Laden.