Once in position, all he has to do is wait: As soon as enemies reach the top of the ladder, the box's enhanced tackle sends them screaming to a horrible death before they have the chance to attack. This would be incredibly annoying if it didn't look so damn ridiculous.
Your character has time to take a smoke break, for God's sake.
Wrecking players armed with devastating firepower by running into them with your recycling is possibly the most satisfying thing this side of popping bubble wrap.
"I CAME IN LIKE A
WRECKING BALL CARDBOARD BOX!"
Plus, the box-related puns are practically boundless.
"Happy Boxing Day."