[Vince]

The HOLDING macro is often used wrongly. What is usually desired is PRESSED and RELEASED. OnPlayerKeyStateChange is only called when a key changes. You can press and then hold KEY_FIRE for an eternity but it will still only register a press when you first press it and a release when you release it. Only if you press an additional while still holding KEY_FIRE will it register as holding.

You will need to set a timer when they first press the key and it and kill the timer when they release it. Alternatively, set and unset a variable and use OnPlayerUpdate if you require faster interaction.