It's a fantasy role-playing game.

DM: You are Vax Vax'ildan, a half-elf rogue . You are the member of the famous group of adventurers. Previously, Three locks' scratchings translate to the Common equivalent of 'open me', one of the locks' scratchings warns the party not to open it. you discovers that the lock saying 'No' is trapped, and the ones saying 'Yes' aren't.
DM: Okay. So you back up-- You notice at this point, as you step five feet back that that weapon he's carrying is pretty long and has a pretty decent reach. You may have to disengage to get out of there without taking another strike.
Player: But if I were to go left or right, would I be out of range of hitting him because of the doorway?
DM: You would be over here, probably, yeah.
Player: So if I move sideways either way I can't hit him?
DM: Correct.
Player: So I'm not going to do that. I'm going to just step back against the back wall and hold.
DM: Are you using your disengage action or not?
Player: Was I within five feet of him? Yes, I'm going to use disengage.
DM: Okay. So you use your bonus action to disengage. Because you're not used to fighting these long polearm weapons, as you begin to take another step back, you realize he can actually hit you from further away than you expect.
