On the surface that's exactly what it is. However, a risk in any warning is that of the self-fulfilling prophecy. Regardless of Medvedev's apparent or actual motivation, the warning could help catalyze the very thing he's presumably attempting to prevent: Russian regime change.
You might be reading too much into it. Most likely it's just a warning not to try anything.
On the surface that's exactly what it is. However, a risk in any warning is that of the self-fulfilling prophecy. Regardless of Medvedev's apparent or actual motivation, the warning could help catalyze the very thing he's presumably attempting to prevent: Russian regime change.