I saw a guy doing this today... (reported him by the way but didn't had time to record it) You can actually go through the wall of the biggest building of the map (wich contain the A point) from the outside.

Like this:
https://youtu.be/XY3HqBLIO7Y

Wich means you can get in without use the main doors.

And.... if this is not enough.... you can actually kill a player that is hinding inside by the same way.... but without getting in.
https://youtu.be/iMFSTzJFPOE

I used the Eden Editor thing to film it so there is'nt any furniture in the building but it seems this path is clear of anything (maybe you should try put some fridge there or watever...)