PS4 Resident Evil 5 Mercenaries United Solo Public Assembly Chris Warrior 150 kills

i know i know, public assembly is the easiest stage for 150 kills. i'm just discouraged after 2 weeks of trying 150 kills with chris warrior in ship deck with no luck. got two 149 kills with time left but not able to find the last enemy. so to make myself feel better. did a 150 in p.a., since i haven't done that yet with chris..