This sequent is not provable.

$\mathcal{M} : p = T, q = F, r = F, s = F, t = F$ \\
$\mathcal{M} \models \neg t$\\
$\mathcal{M} \models (p \land r) \imp t$\\
$\mathcal{M} \nmodels (r \imp s) \land (p \imp q)$
