what I understand is boss goes into rage mode only after enough attack, in this case, enough spike attack (not base on time, but attack number) As long as the boss is not within your screen, the boss won't attack, it moves toward you instead and if this movement is stuck by any obstacle, then the boss is stuck
is your attack only 33-35k? and u get there without even S grade snake? ive gota learn how to play like you lol. i am curently sitting on 32k attack/64k hp 6/6 berserk stuck on chapter 23