「お先に失礼しま～す」「お、なんだ、また定時上がりかよ」

「」「、、」

'I'm heading out~' 'Oh, what, clocking out right on time again?'

Literal

'Ahead [at-に] excuse-me~' 'Oh, what, again on-time leaving [question-かよ]'

お先に失礼します 'excuse me for leaving before you' — the standard Japanese workplace departure phrase. The elongated しま~す adds a breezy, lighthearted tone. 定時上がり 'leaving at the official end time' — in Japanese work culture, leaving on time can be notable. かよ is a rough masculine question expressing mild exasperation.