Sorry
, You do not hold the Glock an inch away from you're ear pointing at the ceiling, whether behind a ballistic entry shield or behind someones head, that's what they do in films when taking cover with their gold plated Desert Eagle. What you should do is hold it at waist height pointing forward to the ground - you can aim that bit quicker, you don't shoot you're colleague in the head and you don't rupture you're eardrum.