A cutter apparatus includes a housing shaped to be hand-held, the housing including first and second handle portions shaped and/or adapted to interfit together, a blade holder configured to support a blade, and a lock/unlock mechanism for securing the handle portions together, the lock/unlock mechanism including multiple actuators operable for extending the blade from the housing, the actuators including a primary actuator coupled to the blade holder and repositionable in relation to the housing, and at least one auxiliary actuator including a first auxiliary actuator supported by and repositionable in relation to the first handle portion. The primary and auxiliary actuators are biased toward and/or repositionable to respective locations at which an aperture of the first auxiliary actuator coaligns or registers with an opening in the first handle portion in an unlock configuration that allows a user of the cutter apparatus to reposition/separate the handle portions from each other.