Complex sentence: They are almost killed, but Goku and Krillin arrive on the scene in time and kill Angila and Medamatcha, but Slug then enters the fray.
Split into simpler sentences: They are almost killed by Angila and Medmatcha, but Goku and Krillin arrive on the scene in time. Goku kills Angila and Medamatcha, but Slug then enters the fray.