10.10.2016, 18:25
Put this on 'OnPlayerKeyStateChange':
EDIT: Sorry for some edits, I wasn't sure about some things. 
PHP код:
public OnPlayerKeyStateChange(playerid, newkeys, oldkeys)
{
if((newkeys & KEY_HANDBRAKE) && !IsPlayerInAnyVehicle(playerid) && GetPlayerWeapon(playerid) > 0)
{
//Do something
}
return 1;
}