If merely looking to elevate into yellow/red levels of arousal through safe means, let me suggest a digital approach: not "ego shooters" but rather 1 vs. 1 competitive Real-Time Strategy (RTS) vs. anonymous human opponents. I'm sure one can build up a tolerance, but a 2-month fling with Starcraft II taught me that stress gets amplified by the following:

1.Complex cognitive demands.

2.Knowing that no-one will come to your aid.

3.Feeling like your opponent has absolutely no reservations about eviscerating you (probably helped by not being able to see them)

I studied the game intently, advanced above the 50th percentile quickly... and had to give it up. By the end of each round I was often too shaky to manipulate my mouse. I would have to run in place and then pace for long periods to lower my heart rate. The clincher, though, was the impact on my temper. I would become enraged at little things, and the mindset could persist for 12 hours or more.

For me, playing felt too much like being a hunted animal. Interestingly, a friend of mine gave up the game for similar reasons -- but described his experience as feeling too predatory, like he was stalking and literally killing his opponents, with resulting damage to his own psyche.

He may have been better than I was.