Application of Hensel's lemma

Question

Show that the polynomial $\Phi(x)=x^2 -2 \in O(\widehat{\Bbb Q_2})[x] $ has no root in $\widehat{\Bbb Q_2}$, even though $\bar\Phi(x)\in E(\widehat{\Bbb Q_2})[x]$ has a root in $E(\widehat{\Bbb Q_2}) $. Reconcile this observation with Hensel's lemma. Here $\widehat{\Bbb Q_2}$ is the completion of $\Bbb Q$ in the $V_2$-topology, $E(\widehat{\Bbb Q_2}) $ is the notation for residue class field and $O(\widehat{\Bbb Q_2})=\{x\in\widehat{\Bbb Q_2}\mid V(x)\leq1\}.$ (Associative Algebras by Richard S. Pierce, section 17.4, page 325, Exercise 3)