入口 and 出口: entrances and exits
Use notices to distinguish a passage's function from a person's actual movement.
A way in
入口 (いりぐち) is an entrance. 「入口で待っています」 means waiting at the entrance. It gives a waiting location, not a completed entry.
「入口が分かりません」 can mean not knowing where the entrance is. It does not mean the building does not exist; identify what is unknown.
A way out
出口 (でぐち) is an exit. 「出口は右側です」 says that the exit is on the right. Check the reference position or orientation of the sign.
「出口まで案内します」 means guiding someone as far as the exit. まで sets the limit; it does not promise accompaniment to a destination outside.
Restrictions on passage
「ここは出口専用です」 means that this passage is for exiting only. It does not say it also serves as an entrance; preserve the restriction marked by 専用.
「別の出口を使ってください」 asks someone to use a different exit. Without an explanation, the reason for restricting the current one is unknown.
Does 「入口から入って、出口から出ました」 say the same passage was used twice?
Show the answer and why
No. It specifies entry through the entrance and departure through the exit. Whether they occupy the same location is separate.