Currently it seems like the buggy dismount trigger when entering a Lab is when you're close enough for the Lab door to open, which is super annoying when fighting near a lab door, or even walking. I build my first base around the first lab door, and when I walk on a base floor above the door, it causes me to dismount my buggy and sometimes makes the buggy disappear back to the nest.
The Dismount trigger should be moved to actual door threshold instead of in the vicinity of the door or when close enough for the door to automatically open.