면서 찾다

search while doing something

"-(으)면서" (while, at the same time as) plus 찾다 "look for, find". It names what you do as you search: keep turning your head to look for them, go in on patrol and search, look for it while reading the reviews carefully, going all over the country searching. It also fits recalling rather than locating — it looked like he was finding his lines while doing the breathing. The searching and the other action run together, not one after the other.