碇 シンジン

Then the fault is from the writer and editors (not bringin enough redundancy on key events for the readers to follow the main plot).

It is common in fanfictions for the authors to use localisms from the place they (or the characters) currently live; while those phrases could be expresed in "simple english", they choose to not do it to increase the "realism" or inmersion of the story.

My advice is to continue the reading until the next "stop sign" (the...

An "stop sign" (if the fanfic is edited correctly) could be the change of PoV from one character to another, the start/end of a dialog between two characters or a detailed description of a place or mental state.

Once you complete the reading of that part, if you still do not understand what happened (or how, or why they are doing it that way), then read the next block [to catch inmediate references] and re-read that part again.

If you still do not understand it...

Then you can skip that part of the chapter as filler and continue (even if it was important), because the continuity should incorportate it later if that was the case (or not, fault for the author again).