Arnold cared little about the operation, and instead turned killing the surrounding zombies into a sport, accidentally shooting Linda when he mistook her for yet another zombie. Upon realizing his error, Arnold continued his game, not fazed in the slightest about whether or not his targets were human or zombie. Upon discovering Raccoon City's impending fate, Arnold abandoned the mission and his unit, choosing to save himself before the missile attack was launched.
Arnold will only be encountered in the End of the Road scenario if the player decided not to detonate the Tyrant's bomb collar before the encounter with Linda. Arnold should be treated as an un-killable sub-boss and regarded as extremely dangerous regardless of difficulty. Arnold will be located on the highway overpass above the area In front of Apple Inn and will shoot at anyone within his range. The bullets fired by his PSG-1 rifle deal massive damage to the player, sending them instantly into Danger status. This, combined with the fact that the area is mined with at least three landmines (which also send the player into Danger status), makes it one of the most difficult moments in the entire game.
However, there's a trick: the bullets are programmed to only hit on the fourth shot. Some characters can actually exploit this, such as Yoko and Cindy with their dodging moves. If timed right, the fourth shot can be avoided. Yoko can simply crawl away as the last shot is fired. Cindy can simply duck when the fourth shot is fired. If she is carrying Linda or an AI partner, they'll duck as well.
The player can also use Linda or an injured partner as a shield; right before the fourth shot, the player can grab Linda or the injured partner, and they won't be hit, but instead one of their AI partners if there are any left. Other than being in this area, he never appears again.
Arnold can be unlocked in Outbreak File #2 by clearing "End of the Road" scenario on VERY HARD difficulty. It can then be purchased for 5000pts. He can then be transferred to File #1 via File #2's data convert feature.
- Arnold seems to have a similar personality to another UBCS leader, Klaus, as he attacked Umbrella Executive Tommy Neilson, similar to Klaus attacking Roger.
- Arnold's line "Ah well, fuck it" makes him one of the few, and the first character in a Resident Evil game to use the word "fuck" in a cutscene. (Certain Characters such as Jim Chapman and Kevin Ryman say it frequently in ad-libs in the outbreak games.)
- He finds his clean up mission as a "hunting excursion", having 100 "rodents" killed in one night.
- His attitude on the situation resembles S.T.A.R.S member Michael Guthrie from the film Resident Evil Apocalypse, as both characters enjoy killing zombies with a Sniper Rifle.