Getting under the map

I was just playing a robocraft 15 min ago and i noticed someone was capping the base but know one was there i looked in the base and someone was there then he saw me and dissipered under the map. does anyone know how to get under the map. not under the base but under the map is there a bug or somthing of how to do this if so I would like to know.

It happends randomly. And its totally useless. You fall and fall and can't do anything.

I know but this guy I saw was a plasma bomber with walker legs and he just flew under the map. and his plane was built for shooting above him so if he was flying under the map he could shoot above him while he flys and kills the person.