Actually, 'bouka' is like something along the lines of fire prevention, 'tobira' is door, and 'shimero' is the imperative / command form of 'shimeru' -- to close.
From my favourite J<->E dictionary site:
??????? (n) fire prevention; fire fighting; fire proof; (P)
?????? (n) door; opening; (P)
???????? (v1,vt) to close; to shut; (P)
Aw, damn. Looks like this forum doesn't support Japanese encoding. Too bad.