Quote shortwavesurfer2009:

The way it would work would be that an arbitrator would create a bot to take the offers and then use the key from the taker bot and their arbitrator key to steal the escrow which contains the seller's Monero plus their security deposit.

Source: nevent1qqs0h2fvwvcsg58l6xw9hwpav4kk3vry933rrm6pparrf0s7p9rel6gpz4mhxue69uhkg6t5w3hjuur4vghhyetvv9uszyrhwden5te0v5hxummn9ekx7mp0qythwumn8ghj7en9v4j8xtnwdaehgu3wvfskuep0mvpr6f