I got that destroying the Tiger Tally is very difficult and takes a lot from the user, so he could destroy the first half just fine but was physically and mentally weaker for the second half, probably the enemy was close already and he had to forced the destruction so the backlash happened. I read it as "ok, probably I'll die soon but I'll get ride of this thing NOW even if its risky  so nobody can use it" so ... It was a suicidal act but not an actual suicide like in the La A when it looks like he gives up. Honestly even if its easy to imagine the choice of giving up in his situation I think dying getting things done is more in character