What episode/film of Detective Conan does Hattori Heiji "almost" die?

He's working on a case on a big bot with Conan, Ran and Mouri I think. The killer throws him atau hits him over the edge when he finds out who it is though, and anda think he's dead as it's ocean. If it's any help, I think it might be the same episode where Ran is karate fighting a man who seems to have great skill as to hers (but not Sera though)