The last thing Vendata says to Brock in Bot Seeks Bot is "I think the plane is going down" after implying he saw Jonas hooking up with his wife. Most likely Jonas got caught banging TM's mom, and possibly after being brought back by Jonas, Vendata's memories resurfaced and tried to kill Rusty as revenge.

In my best estimation, the "Milk Look" was because he would need to keep milk in the fridge, which is probably not functioning do to lack of electricity.