Space isn´t merely outside the object, holding it at its boundaries. It is inside it too.
This meditation uses again the pointing out metaphor of space. Space is a metaphor for awareness, for the container, for the "condition" in which everything appears.
In Tibetan writings, one particular property of this metaphorical "space" (of awareness) is that it "permeates" everything. Space permeates objects. In this sense, there is no boundary and no separation between space and objects
The metaphorical value is that there is no separation between awareness and the objects of awareness. Awareness permeates everything. Or, in Sam Harris' preferred language, all objects and events are an expression or an "articulation" of consciousness
The expression therefore supports a non-dual view.
Of course, in today´s physics, this view has a scientific foundation. For example, our sense that there are real hard objects out there (like the cup that I see on the table beside my laptop), is deceptive.
If I had a giant electron microscope I would see that there is eventually nothing except molecules, atoms, and subatomic particles in various constellations, indistinguishable from the molecules, atoms and subatomic particles of the surrounding air, and if I go deeper, I would see quantum particles popping in and out of nothingness.
The sense that there are hard impermeable objects is just based on the movement of molecules at different speeds.
This is a wonderful movie about nothing...
Everything & Nothing [2/2] - video Dailymotion. (n.d.). Dailymotion. https://www.dailymotion.com/video/xuh17e