Because of safety concerns. If it falls into the tank or gets damaged from not being out of the way in a storage area it gets ruined. Comes down to, "we can't/won't afford to replace these more often than we have to, keep them somewhere where they won't get broken."
Both good points. We don't know whether it's actually secured, do we? Nothing's shown up yet, but you never know, it might be far enough away to not have heard the scuffle, or might be stalled or lost.
It's definitely not a good situation, but we have to do something. The filter is the more pressing concern, since we don't know where one will come from or if there will be any near where they get put in. But, to get started with that, we need to get the bodies out, which is why I voted for that