It's simply lack of absolute confidence. You don't see anyone behind the book because you at least slightly believe that the technique will fail. All techniques within the phase work but only if you believe they will. With this in mind you can do anything you want.
An example of this is deepening. In the practical guidebook deepening is needed because the phase slowly loses clarity overtime and becomes blurry. Eventually it will fade to blackness and all your senses will disappear along with the phase. To counter this the practical guidebook states that you must palpate your surroundings. By doing this the phase will become clearer and ultra realistic... Because you believe it will
Yep, that's right. Whatever you believe will deepen the state will actually deepen the state. So if you think saying "deepen" out loud within the phase will deepen the state then it actually will. The reason micheal using palpation however is because the feeling of touch is usually more immersive and can be used in more situations. When in complete darkness within the phase touching things is potentially more effective to create vision than simply saying "deepen". This is because vision is more easily generated from touch rather than sound. Or maybe it is just because we believe it is
Overall though the main point I want you to get out of this is that you must absolutely believe a technique will work without a doubt. If you can master your confidence you can master control of the phase. This is similar to phase entry itself. If you believe you can easily enter the phase by successfully performing techniques then you will. Although phase entry is much harder to tackle using this method so don't worry about that just yet...
At one point I believed I was trapped in the phase and unable to awaken physically. By believing this I actually did become trapped in the phase. I didn't need to deepen, maintain or do anything to remain in the phase because I didn't think I needed to. Instead I was trapped in an endless cycle of completly conscious false awakenings begging and hoping to truly awaken. It wasn't untill I became extremely desperate believing that with extreme hope I could wake myself... It worked
You can read about that here:
http://obe4u.com/phpBB3/viewtopic.php?p=4346#p4346
Anyway good luck
Maybe try to create your own technique such as closing your eyes and time traveling to the last time you met that person in real life. Time travel and teleportation to a place where they were previously may be easier than trying to insert them somewhere else... As long as you believe it is
