The big question ‘Flatline’ is how aware the Boneless of their actions. We’ve already seen that there have been attempts at communication, emulation and camouflage. What might be the reason that the Boneless from the mural might pursue Clara and the community workers?
This could simply be a response to a perceived attack, in this case the attempt to paint over them. As a 2D entity being covered by the paint could be seen as a means of confinement or an attempt to smother them. Their pursuit and subsequent attack is thus retaliation.
If the Boneless are indeed attempting to infiltrate then their attack could be a means to eliminate those who are obviously aware of their presence, just as they targeted the victim in the teaser only after he attempted to warn others of their existence.
This could be a continuing part of their experiment. The mixture of age, gender and race amongst the community workers and Clara could be perfect to test the Boneless various theories about humanity. The scenario could specifically designed to see how different humans react to the threat.
The presence of the TARDIS itself might also be a factor. It is demonstrated several times that the Boneless are draining energy from the TARDIS. Each time they do the TARDIS shrinks or its systems shutdown while the Boneless gain new abilities. If true the Doctor has once again put others in danger just by being there.
The Doctor attempts to communicate with the Boneless through mathematics, using pi as a basis. The Boneless are able to respond, transmitting a chirping sound which the TARDIS translates into numbers.
The first number is ‘55’ which Rigby believes relates to the number of the community workers wear. Stan, the recent victim in the underpass, was 55. This could be true and either be the Boneless gloating, as Fenton believes, or an apology, as Clara suggests.
They might also be referring to the 55 that hangs on the wall next to George. Indeed his number is ‘22’ and they absorb him next. While this could again be the aliens taunting the group it might also be the Boneless describing their path across the room.
Aside from this the Boneless don’t appear to be able to communicate. None of them speak and we can’t be sure that they understand anything that is said to them. If they are truly alien the TARDIS might not be able to translate the Doctor’s speech for them, leaving them entirely puzzled by the whole affair.
Unless brought into the 3D world by another agency the Boneless must have enough intelligence to add dimensions to their own. While they are shown to drain power from the TARDIS they have been active in the area before it arrives so they must have been able to make that first step themselves.
If you wanted to tie the Doctor more closely with the creation of the Boneless it could be supposed that the TARDIS was coming from the past into the present. As it passed through the last few weeks as it approached its destination the Boneless first got their taste of its dimensional power and realised they could use it to shift into 3D. This would explain why the TARDIS exterior has already shrunk by the time it lands.
While the Boneless later demonstrate the ability to alter dimensions physically it must be remembered that this is done only through the avatars of their dead victims. This need not be a natural ability. If it were one would think that such encounters were more frequent.
It is possible that the Boneless are making use of some 2D technology which is never seen (and might be integrated into them). This technology could be part of their snake like form we initially are shown, since it is three dimensional (rather than truly flat).
It could be that the technology is only a minor step for the Boneless, it is the understanding of dimensions that is the important part. Much like block transfer calculations learning the principles allows them to control their own reality. The Boneless are slowly learning more about our world and the more they learn the more they can do.
In only a few hours the Boneless go from near invisible flat beings to being able to create 3D humanoid forms. They are not restricted to just copying forms either, as they are able to create a giant hand to snatch one victim away.
This might appear to be rapid progress but we have no idea how the Boneless view time. Indeed they are able to rapidly dissect PC Forrest and manage to absorb Stan and George before they can make a noise.
From their perspective much more time could be passing. To them this period of development could take days, weeks or months. This extra time to contemplate and interpret what is happening could compensate for their lack of experience with this new realm.
The accelerating rate of their abilities is almost certainly due to the TARDIS. Somehow the Boneless are able to remotely draw upon its power remotely. They seem to be able to do this from quite some distance, although the Doctor initially believes that Clara can move it out of range when he senses the Boneless during their investigation.
Could their ability to interact with the TARDIS reveal a connection to Gallifrey and the Time Lords. We know very little about the actual process involved in making the TARDIS bigger on the inside but some of the books indicate that there is a threshold bridging the exterior and interior dimensions.
While both of these dimensions are three dimensional in theory the same threshold could be used to pass from a two dimensional space to the three dimensional. The Doctors flippant remark about needing to diet to get to the 2D plane could indicate that three dimensional creatures would be crushed if they went there but there is no reason that 2D beings, such as the Boneless couldn’t make the trip the other way.
The Boneless could be the equivalent of bacteria, growing within the TARDIS threshold. The Time Lords might have experimented with other dimensions and stumbled across the 2D plane, only to find that they couldn’t access it but their influence still allowed the Boneless to be aware that other life existed.
In their own realm the Boneless might be the equivalent to the Time Lords. Indeed their power over the three dimensional could make them as god-like to two dimensional beings as the Time Lords’ mastery over 4 dimensions was to other races.
To Be Continued….