The system saves (Doom Eternal)

Overall a retarded saving system. Or I do not understand something, tell me. Let's say I reached the 5th Chapter and decided to re-take a 2nd Chapter to get missed secrets and the arena. In the middle of pereprohozhdeniya 2nd Chapter took to get out of the game... I never understood how when you next start the game, continue passing from the scene where I left off in the 2nd Chapter? If you choose to Continue I will be in last place of the passage, i.e., in the 5th Chapter. You can also select any previous Chapter, but it starts from the beginning.