Michael Weston, a trained CIA operative and former special forces operator, is shown frequently holding his semiautomatic handguns in a "teacup" position. This is when the handgun's magazine well is shown to rest upon the palm of the weaker hand in an effort to steady it.
Not only is this an incorrect grip as it doesn't assist in steady the weapon when you fire it, a failure of round in the chamber could send shrapnel and heated gases through the magazine butt plate and into the shooter's hand. An experienced agent would know this and would never hold a weapon in this manner.
For what it's worth, the correct terminology is "CIA officer," not "agent." To CIA, an agent is a recruited spy, not a full-time, official CIA field employee. Apparently either a CIA officer or a CIA agent could be called a spy. This confusing terminology probably is because the FBI calls its folks "FBI agents".