Complex sentence: But when Hammer sees Haggis'red shoes, he starts to snap and pulls his.44 Magnum Smith & Wesson Model 29 revolver at Rinsler, who tells him he's supposed to kill Theiss; thus confessing to the brainwashing incidents.
Split into simpler sentences: But when Hammer sees Haggis'red shoes, he starts to snap and pulls his gun. However, he points his gun at Rinsler, who tells him he's supposed to kill Theiss; thus confessing to the brainwashing incidents.