  In this paper, we discuss the black hole complementarity and the firewall
proposal at length. Black hole complementarity is inevitable if we assume the
following five things: unitarity, entropy-area formula, existence of an
information observer, semi-classical quantum field theory for an asymptotic
observer, and the general relativity for an in-falling observer. However, large
N rescaling and the AMPS argument show that black hole complementarity is
inconsistent. To salvage the basic philosophy of the black hole
complementarity, AMPS introduced a firewall around the horizon. According to
large N rescaling, the firewall should be located close to the apparent
horizon. We investigate the consistency of the firewall with the two critical
conditions: the firewall should be near the time-like apparent horizon and it
should not affect the future infinity. Concerning this, we have introduced a
gravitational collapse with a false vacuum lump which can generate a spacetime
structure with disconnected apparent horizons. This reveals a situation that
there is a firewall outside of the event horizon, while the apparent horizon is
absent. Therefore, the firewall, if it exists, not only does modify the general
relativity for an in-falling observer, but also modify the semi-classical
quantum field theory for an asymptotic observer.
