[Doctor Raoul]

Feet laid flat. Only the untrained has their toes straight down and heels straight up.

The advantage?

[Blue Jays]

By keeping one’s feet flat and close to the ground, one minimizes the opportunity of catching a sniper’s bullet to the heel. The more one has cover and concealment, the better.

[Tonytitan]

It provides a more stable shooting platform. Wiggling feet can wiggle a weapon so that a wiggly shot is sent downrange.