I presume this is the old old story of a word slowly creeping into metaphor and then developing a new identity.

To escalate = to raise (originally by means of...?)
Ergo escalating violence = violence levels rising (on both sides in response to each other?)
Ergo escalate = taking action at progressively higher levels of command to deal with escalating violence etc

from which thermonuclear scenario we then achieve bathos

to escalate a customer service issue = to send 'upwards' to someone who knows what she's doing, since the poor bugger on the end of the phone has used up all his resources when he reaches the end of his laminated script.

What I want to know is, when will it escalate to defcon1?