Topological Properties of Non-Archimedean Division Rings/Intersection of Open Balls

Theorem
Let $\struct {R, \norm{\,\cdot\,}}$ be a normed division ring with non-Archimedean norm $\norm{\,\cdot\,}$,

Let $d$ be the metric induced by the norm $\norm{\,\cdot\,}$.

For $a \in R$ and $\epsilon \in \R_{>0}$ let:
 * $B_\epsilon \paren{a}$ denote the open $\epsilon$-ball of $a$ in $\struct {R,d}$

Let $x, y \in R$.

Let $r, s \in \R_{\gt 0}$.

Then:
 * ${B_r} \paren x \cap {B_s} \paren y \ne \empty$ ${B_r} \paren x \subseteq {B_s} \paren y$ or ${B_r} \paren x \supseteq {B_s} \paren y$