This works, but it shoots by really fast:
waituntil {!isnil "bis_fnc_init"};
["Passing 500 meters!",[getPos player select 0, getPos player select 1, 500],50,0] call BIS_fnc_3Dcredits;
I however was not able to get multiple messages to show up as I fell, like at 300m and 200m for example. Not sure why really.