Consider the following premises. q_4 or u_3. s_2 or ~u_3. ~q_4. Can we infer s_2 from them?
 From q_4 or u_3, ~q_4 we can infer u_3. From s_2 or ~u_3 we can infer u_3 -> s_2. Finally, from u_3 -> s_2, u_3 we can infer s_2. Therefore, the answer is yes.