PEACE
If peace = 0 then ????s is proven because the ea in PEACE was also present in YEARS. It can't be the r because years had only 1 hit. Neither can it be the Y because of ASHES. Hence, last letter is proven to be S.
What? This isn't saracasm. What you just read was saracasm.
Also, it is always possible to make a bomb from the most nonflammable items in the known world ( I.E., a paperclip and some gum )
"Oh. So, you want us to risk our lives watching a fierce monster and gauging how long it's prison will hold, With every chance that it'll break loose and kill us before we can get word to you?" Flame says dubiously. "Just checking."
"Well, I guess were on our own... honestly, I just hope that it's not the execution chamber or anything... or am I being to paranoid?" Flame mutters to himself, then starts to follow the sentry's instructions.