Back when he'd just been the Doctor, on the rare occasions when he'd found himself forced to deal with dimensional barriers and experience the Gardner Effect for himself- most disturbingly in those cases where he'd visited a world where his life was a television series- the thing that had intrigued him the most was how many variations of the fictional worlds could exist, or how much detail the writers could receive about the more complex details about their other worlds.
Obviously, warp drive didn't work exactly the way it worked in the Star Trek universe, and there wasn't really such a dimension as that 'Speed Force' that had been created by DC Comics, but the central ideas behind the principles involved were at least accurate in the worlds they came from, even if they wouldn't work in other worlds for various reasons. Most of those worlds and their variations remained separated from other universes expect in extreme circumstances, but there were a few occasions where certain worlds could 'overshadow' other histories if the right events happened to allow people to access some of those unique forms of energy.
The area that he was visiting now was one such location, ever since its research had allowed it to tap into a very distinctive source of other-dimensional energy used in another reality. As a result, it now existed at a point in time and space where the events that could take place inside it could easily 'overwhelm' the reality that he knew at some point in the not-too-distant future if some significant event occurred.
When he'd learned of the link that this facility's experiments had created to a different world, he had been briefly tempted to try and assist that other reality, but had decided against it in the end. While he could make it easier for the heroes of that world to defeat their villains, stepping in like he usually did would have deprived so many people of the opportunities to grow as individuals that they had been presented with during their conflicts, and most of the villains had proven to be relatively ineffectual in the end anyway; they'd never even managed to permanently kill one of their foes.
In this case, however, since the villain in question would have destroyed the world before the heroes could assemble against him, he felt it appropriate to take action in this case; giving the heroes a chance to grow was less important than preventing meaningless death on such a massive scale.
Tracking down the facility had been tricky, of course, but once he'd learned of its existence in the future where things had gone wrong, it had been relatively easy to make his way inside.
According to all available records, the woman who would become known as 'Doctor K' was destined to be captured along with her friends when she attempted to escape in a few moments, which meant that, based on the map he'd acquired of this 'Alphabet Soup' organization and their base, all he had to do was wait at his current junction until…
As the soldiers came hurrying along the corridor, he pulled out his weapon- a smaller energy blaster than the weapon he'd used to kill General Quaritch on Pandora, but it would get the job done- and fired a quick series of shots before the soldiers knew what was happening.
It was almost disturbing how easily they went down, but that was the main advantage of fighting Daleks; he would never sympathise with them because he knew what they had done to themselves in the name of their twisted quest for 'purity', but in this case, even if he disagreed with their methods, these soldiers were only doing their jobs for what they believed to be the 'greater good'…
Still, if their deaths now prevented the release of the Venjix virus, it was a comparatively small price to pay. Without these soldiers to prevent Doctor K from installing the firewalls to limit Venjix's ability to access external networks, it would be easy enough for her and her friends to escape while the rest of the staff were focused on regaining control of their own computer networks.
Proportionately, the decision made sense; kill these few now, and the timeline where Earth was decimated by Venjix's forces would never come to pass, and every single person killed by its robots would live.
If he kept telling himself that, maybe he'd eventually convince himself to accept it.
Still, with the innocents out of the picture, all that was left to do was use the distraction caused by Venjix and activate his own little virus, programed to set this entire base to self-destruct. With the power cores set into a continuous overload while leaving the doors unlocked, he was confident that he'd left everyone still in the base enough time to evacuate before the explosion.
He couldn't stop all of the various threats that the Power Rangers would have to face in their dimension, but in this world, he could spare them from the horror of Venjix's conquest of the planet.