This tier 5 was so close :D
Build order is :
200 farm
Ben
000 engi
320 farm
004 engi
030 engi
420 farm
040 engi
140 spike factory
005 engi
150 spike factory
520 farm
500 engi
050 engi
engi paragon
engigon placement is important here as he won't be able to immobilize the last soul if placed further away from the exit.