Working with form methods in Sinatra

An example of the form method from a view

<form method="get" action="/input">
  <input type="text" name="input"  /> 
  <input type="submit" value="Submit" />
</form>

What I have

get '/input' do
  @input = params[:input]
end

get '/' do
  @torch_room = torch_room
  @location == @torch_room
  case @input 
  when "go northwest"
    redirect "/chest_room"
  when "go north"
    redirect "/dais_room"
  when "go northeast"
    redirect "/orb_room"
  else
    puts "I don't understand what you just said."
    erb :torch_room
  end
end

Works but SO UGLY

get '/input' do
  @input = params[:input]
  case @location
  when @torch_room
    case @input 
    when "go northwest"
      redirect "/chest_room"
    when "go north"
      redirect "/dais_room"
    when "go northeast"
      redirect "/orb_room"
    else
      puts "I don't understand what you just said."
      erb :torch_room
    end
  end
end

Works, but SO UGLY

get '/input' do
  @input = params[:input]
  case @location
  when @torch_room
    case @input 
    when "go northwest"
      redirect "/chest_room"
    when "go north"
      redirect "/dais_room"
    when "go northeast"
      redirect "/orb_room"
    else
      puts "I don't understand what you just said."
      erb :torch_room
    end
  end
end