If the door is in the same room you could do something like this:
scene_info = [
[cutscene_fade_out,3,c_black],
[cutscene_camera_follow_object,obj_door,10], // Alternatively cutscene_camera_moveto_position
[cutscene_fade_in,3,c_black],
[cutscene_wait,1],
// Here use some script to show the door unlocking,
// for example cutscene_set_sprite or cutscene_change_variable
// depending on how it works
[cutscene_wait,1],
[cutscene_fade_out,3,c_black],
[cutscene_camera_follow_object,obj_player,10],
[cutscene_fade_in,3,c_black]
];
But to be honest, the cutscene_fade_out and cutscene_fade_in scripts are not very good currently, there is a flicker if using some script in between. I will fix that in the next update probably, but I can give you a quick fix if you need it.