When i was in the Army, during MOUT exercises, i've been in the same room as an M-2 .50cal HMG blasting away into the night, blasted off belt after belt of 7.62mm, and been in a foxhole not 30 meters from an M-1 firing off it's 105mm gun (120mm wasn't fitted until the A1 models).
Pistol blast, report, and muzzle flash is something that i consider to be a total non-factor until you get into the big magnum loads. Especially when your adrenaline is pumping in the middle of a fire fight.
Of course, opinions vary.
Trust me, compared to that, the flash from your pistol is a non-event.
M193 US Military/NATO 5.56mm muzzle blast from M-4 carbine