so simple trigger event is not good enough?

function door_event
{
if(event_type == event_trigger) && (vec_to_screen(me,camera) ==1)
{do action;}
}

action door_action
{
my.enable_trigger = on;
my.trigger_range = 200;
my.event = door_event;
}

or
function door_event
{
if(vec_dist(my.x,player.x) <= 200) && (vec_to_screen(me,camera) ==1)
{do action;}
}