A Story from 宇治拾遺物語 (Part 2)

此児、「定めて驚かさんずらん」と待ちゐたるに、僧の、「物申しさぶらはむ。驚かせ給へ」といふを、うれしとは思へ ども、「ただ一度にいらへんも、待ちけるかともぞ思ふ」とて、「今一声呼ばれていらん」と念じて寝たるたり程に、「や、な起し奉りそ。幼き人は寝入り給ひ にけり」といふ声のしければ、あなわびしと思ひて、「今一度起せかし」と思ひ寝に聞けば、ひしひしとただ食ひに食ふ音のしければ、ずちなくて、無期の後 に、「えい」といらへたりければ、僧たち笑ふ事限りなし。


This acolyte waited, thinking that certainly they'd rouse him, when he heard a monk say "Let's call 'hello' to him to wake him up." He was happy, but, thinking to himself "If I answer after just one call, they'll think I was waiting. I'll answer after they call again," he just stuck it out and continued to pretend to sleep. Then, when he heard a voice say, "Don't wake him up. The kid fell asleep on us," he thought he was in a bad spot. "Wake me up again," he was thinking as he continued to sleep and listen hopefully. Then there was a "chomp chomp" sound. With no choice left and having waited so long, he answered, "Yes?" The monks all laughed without stopping.

I broke down and found a modern Japanese translation of this to sankou suru. This part has some real marathon sentences as well which I just had to chop up to get semi-readable English. Can anyone tell me how this しければ works?