monsters that are piled up combine strength(*) to bash things
*: only the primary basher (mob right infront of door) benefits
*: only monsters directly behind the primary basher add 100% str, others add 50%
*: this pools monsters up to 5 tiles behind the primary, and up to 1 tile on either side
ex: P: primary (100% str=2), 2: helper (100% str=2), 1: helper (50% str=2), 0: disqualified monster, -: wall, +: door
.0210
.021.
--21.
01P1.
--+--
.....
total = 13; 2 + (2*3) + (1*5)