One convoluted theory I’ve seen is that the telekinetic guy does everything by pushing oxygen(?) into the room which increases the air pressure and temperature hence everyone sweating (not from heat but bodily chemistry) as he saturated the room. He pulls the button from Hamish’s hand and pulls the wires out the pool meant to electrocute David and they energize the primed air.

It is possible that David is behind is though as it seems excessive that the telekinetic guy could do so much from outside the building, though presumably he could have sight through a window.

What I do know is that David is possessed by the Shadow King at 2:22 when threatened by a soldier.. He sees the Shadow King a minute or so later on the beach as he frantically questions Sydney about how stable his reality is. So I also think it’s possible that David makes the remote disappear from Hamish’s hand, which is something trivial for him, and that he causes the very potent (the men are reduced to charred skeletons in a flash, not a blaze) flash as a subconscious self defense mechanism.

Such a power is a staple for comic book Legion and I believe that when he is possessed by the Shadow King later on and assaults the Division 3 headquarters, he uses the same power.