Why Did Gregory Kill Cassie in FNAF: Security Breach — Ruin?

In one of the endings for 'FNAF: Security Breach — Ruin,' players watch as Gregory betrays and supposedly kills Cassie during her escape. But why did he do it?

All 'Five Nights at Freddy's: Security Breach Ruin' Endings, Explained

Why Did Gregory Betray Cassie In FNAF Security Ruin?

Five Nights at Freddy's Security Breach - RUIN

Five Nights at Freddy's Security Breach - RUIN

Procrastination — Cassie going through walls wearing that Vanny

All FNAF Security Breach Ruin DLC endings, explained - Dot Esports

FNAF SB Ruin - All Endings Explained; Scooper Ending and More

FNAF Security Breach Ruin DLC: Story, Characters, & Price

Five Nights at Freddy's Security Breach - RUIN