I found edge of the map :D

[Szakal_Wu]

Here (NE from spawn) u can swim off the edge of map and fall into the void

[Szakal_Wu]

[TheQuagmire]

Can confirm, While reaching the edge what seems like a possible secret cave to swim into. Your character proceeds to exit the map boundaries, and fall endlessly through the skybox eventually hitting the instant death layer.

[Michael_Proulx]

I can confirm too