The Sentinel Beam is not exclusive to the 3rd Halo game, just FYI
Yeah it is, its just hard to find in campaign, but you could just spawn it in Multiplayer.
In Halo 2, it first appears on The Arbiter, where Heretic Elites used it as a weapon to attempt to stop the Arbiter and his allies from eradicating the Heretic force, in the Gas Mine. Flood Elite Combat Forms then used it on The Oracle, since almost all of the Elite forms were once Heretic Elites. Many of these weapons appear on Sacred Icon and Quarantine Zone, where the stronger blue beam versions were available from the many destroyed Sentinel Majors.In Halo 3, It first appears on The Ark, where it can be gained by picking one of the Sentinels being destroyed (by you, although they may attack you if you destroy too many, or the Covenant Loyalists) patrolling the area. Then it was seen on The Covenant, where some Sentinels were tasked to aid the Arbiter and John-117 in their escape from the Flood in the Ark's Citadel. When Master Chief, the Arbiter and Johnson arrive on the new Installation 04B, they had to clear the Flood blocking their way to the Control Room with the assistance of Sentinels. When one of the Sentinels is destroyed, the Sentinel Beam will remain intact. When the monitor 343 Guilty Spark was destroyed, and the Halo ring activated, Sentinels turned on the escaping Spartan and the Arbiter, which caused several casualties and left their Beam weapons collectible to them.
Good day sir
http://www.supercheats.com/xbox360/guides/halo3/images/sentinelbeam.jpg ?
Because we need more halo stuff because its like we dont have them all.