happend in one of my games, my opponent lost his focus and tenuki'd
(;AP[goproblems]AB[sb]AB[sc]AW[sa]AB[rd]AW[ra]AW[rb]AW[rc]AW[qc]AB[qd]AB[pd]AB[od]AB[nd]AB[md]AB[oc]AW[pc]AW[ob]AW[nc]AW[mc]AW[mb]AW[ma]AW[na]AB[lc]AW[lb]AW[kb]AW[ja]AW[ka]AW[la]AB[kc]AB[jc]AB[jb]AB[ia]AB[hb]AB[pa]C[White to live](;W[oa];B[pb]C[White dead])(;W[qa];B[pb]C[White dead](;W[sd];B[sc])(;W[oa];B[nb]))(;W[qb];B[oa]C[What were you thinking?])(;W[sd];B[oa]C[Even if that group escapes, not a good result with a lot of dead stones])(;W[pb]C[Correct answerRIGHT]))