No, vector() returns a temporary vector, which means, it cycles through 64 pre-created vectors and returns a pointer to one of them (round robin style)
so if you remove a vector, you will most likely get a crash, but even if not, you won't get predictable behaviour and bugs one cannot comprehend
the function most likely looks something like this:
VECTOR storage[64];
int index = 0;
VECTOR * vector(var x, var y, var z)
{
VECTOR * vec = &storage[index];
index += 1;
if(index >= 64)
index = 0;
vec->x = x;
vec->y = y;
vec->z = z;
return vec;
}