you are able to put your buildings on the rocks (primarily your teleporter exit) that are all around inside the tunnel of bigrock.
the rocks within the said tunnel have no navigation mesh, and using said exit will cause the bots to refuse to shoot you, as you are preserving your nav elsewhere.

the only real exception for them to shoot you are as follows:

• you have touched a part of the navigation mesh
• a player (or a players' sentry/dispenser) is within the bots' line of sight will cause the bot to prefire and readjust their aim towards said player and/or building(s). this is relatively easy to avoid, especially with the upgrades you have in dispose within the gamemode.

examples included are within the imgur link:

https://imgur.com/a/NhzJFbv