When Lena's and Kane's hands were touching at the beginning of the movie and their hands were refracted in the glass of water, it was obvious the director wanted us to take notice. Knowing at the end that Kane is in fact a copy created from the "refracting" alien organism, one sees the foreshadowing/hint that was meant with the glass of water in the beginning of the movie.
This idea of refractions also seems to be the point of the movie's final shot when we see the alien + mutated human inside a glass cage. I won't try to dig into any deeper meanings here, but you can tell the intentionality of the shot.
One of the reasons that the movie leaves me satisfied is because it motivates me to remember scenes and realize their narrative purposes. There are themes of dualities here: Creation vs Destruction, New vs Old, Acceptance vs Denial, Eternity vs Impermanence/Transience. I would even say that the theme of the enlightenment of the ego (or lack thereof), in a strongly Buddhist sense, is present in the movie.
Kane and Lena lived in a destroyed marriage. It had already been decaying because of Kane's absence but the killing blow was Lena's infidelity. I have heard it said that when this happens in marriages where you choose to stick together, you never restore what you once had. You have to create a new relationship. New trust and intimacy, flavored with the burden of past history.
I believe that Kane's alien clone and Lena's mutated nature is a parallel to this transformation that married couples go through when one or both have betrayed trust. Sometimes a transformation that can be so dramatic that you might as well say that the old person/relationship was killed and that a new person/relationship was created. The old suffered
ANNIHILATION (BOOM! Title drop!). Just as Cass Sheppard commented: Her old person was killed when her own daughter died. See? Every scene matters. Well, almost every scene.
So what was the point with Lena getting a "bruise" that is seemingly what changes into a tattoo that looks like an infinity (∞) sign?
I believe that the infinity tattoo brought on by mutation represents continuity even in the face of change. Lena may be mutated and no longer be the same person she was before, and her relationship with Kane is certainly no longer what it once was, but there is still a continuity: An abstract, intangible
soul that carried a set of kinetic motions from the beginning all the way to the present.
This theme is even more linked to Lena due to her dialogue about how she would be immortal if only her cells would divide indefinitely.
You take a cell, circumvent the
Hayflick limit, you can prevent senescence. It means the cell doesn't grow old, it becomes immortal. Keeps dividing, doesn't die. They say aging is a natural process, but it's actually a fault in our genes.
Here is where the movie is incomplete and imperfect in its description of biological immortality. But let us assume that what Lena is talking about is immortality through constant, perfect regeneration. No shortening of the telomeres which leads to imperfect copies of genetic data, thus contributing to the biological breakdown of the entity. I speculate then that the reason for Lena gaining an infinity tattoo means that she achieved immortality. Either she literally became immortal, in that the Shimmer mutated her genes so that she now has indefinitely perfect cell division, which might also explain why Lena is able to keep her lucidity throughout the experience. Or she found philosophical immortality by accepting the constant death and regeneration of all things.
Whenever anybody brings up the "immortal" jellyfish
Turritopsis dohrnii, a philosophical contradiction screams back at us. Surely, one could say that when each cell in a biological body has been replaced, the
old body is dead and a new one is created. Having perfect cell division doesn't mean that cells can't break down or that its components are forever. The
ship of Theseus is screaming at us, alongside the immortal jellyfish and the theoretical immortal Natalie Portman.
Yet personal reports from a human being, even after all their cells have been replaced, is that at no point have they died. The change has been too gradual. There is still a sense of continuity, the personal claim of a
soul.
In this way, immortality is married to impermanence. Life and death, creation and destruction, are intertwined. This is why we find the Shimmer to be reported in contradictions: It creates new lifeforms but it also causes the minds of our main characters to break apart. In the lighthouse, Dr. Ventress (which I believe to be the combination the original Dr. Ventress and her alien copy) claims that the alien will destroy and divide all. To her, the alien is only decay, not creation. Yet decay, to fertilize the earth, is an essential part of the underworld that feeds the growing flowers. This may also be why the Dr. Ventress human+alien hybrid is presented briefly without eyes: She is blind to the truth of how creation and destruction are intertwined. Dr. Ventress was naive in hoping that the person who reached the lighthouse would be the same one who entered the Shimmer: She erroneously believes in a constant, solid, unchanging state of being. Of course then she is the one who believes the alien to be ALL destruction and disintegration.
I do not think it's a coincidence that the final goal of the journey is the lighthouse: A source if illumination, or shall we say,
enlightenment. The
Shimmer is merely the prelude, or the hint, to the possibility of enlightenment. In his final moments, the real Kane sits down in a meditative position, close enough to the lotus position associated with east-asian religious practices and the enlightenment of the Buddha.
Kane experiences ego death as he encounters his alien copy. With the dissolution of his self, he lights himself on fire using a flash grenade. Not only is enlightenment of consciousness associated with, and sometimes visually represented with, intense flashes of light but this act of suicide also reminds us of the Vietnamese Buddhist monk
Thích Quảng Đức's self-immolation (and those monks who followed his example).
There are even more ways one can observe how the themes are woven together. The alien copies can on more levels be viewed as representing theories of consciousness, both scientific and philosophical. Then there are the themes of life and death...
Cass Sheppard reports that she died when her own daughter died. She is the living dead. I do not think it is a coincidence that she was the first to be killed off and then manifest as a literal LIVING DEAD via the mutated bear! She is the ghost that defies physical death.
Josie tried to feel alive through self-harm and initially she was the most shocked in the team by all the death and gore around her. Ultimately though, she accepts death and literally becomes one with nature by turning into plants. There may be some theme as to how she conquered her fear by being the one who killed the mutated bear, the manifestation of the living dead, but I can't see what the intention might have been here.