The perversion of the term "mindful" in public language...
While this term is probably not the term used by Zelensky but by the translator from Ukrainian, it shows how the term "mindful" is being bent to connotate "thoughtfulness" or other generally positive criteria. Or, how it is thoughtlessly used as synonym for not forgetting something; taking something into account.
The original meaning is entirely different.
"Mindful" refers to a particular awareness state where the mind is aware of its own activity. It includes concepts such as meta-cognitive awareness, which is the ability of the mind to be aware of its own state in real-time.
So, originally it has a deeper meaning rooted in the practice of Buddhist meditation.
Seeing in a war context, where thousands of people are slaughtering each other, driven on by political power play, is quite annoying.