Omar's mouth moves in the formation of curse words. That much is instinctual. It breaks his concentration and he gasps for air. Gasping for air is painful, and in addition to being decked by the bowl, he's grasping at his throat. The gun drops and bounces on the floor.
Suffocation is silent, much like drowning. The body slowly stops working. It's rather peaceful when you think about it, and over relatively quickly. Being on the end that's causing the suffocation is something different too.
Once Omar's body let's go, there's no turning back. He can't concentrate on anything else, and he can't do anything else. He slowly slumps over in his steel pants, his body slowly giving up.
Omar's at 2L4B and will proceed to die unless Star is going to change course. No need to stay in initiative.
Finally suffocating.