半路

halfway / midway / on the way

half / semi- / incomplete / (after a number) and a half

surname Lu

road / CL:條|条[tiao2] / journey / route / line (bus etc) / sort; kind

switch to a job one was not trained for

lit. Cheng Yaojin ambushes the enemy (saying) / fig. sb shows up unexpectedly and disrupts the plan / sb whose presence is regarded as irksome

see 半路殺出個程咬金|半路杀出个程咬金[ban4 lu4 sha1 chu1 ge4 Cheng2 Yao3 jin1]