dispatch (v.) [<--] 1510s, "to send off in a hurry," from a word in Spanish (despachar "expedite, hasten") or Italian (dispacciare "to dispatch"). For first element, see dis-. The exact source of the second element has been proposed as
[1.] Vulgar Latin * pactare "to fasten, fix" or * pactiare,
[2.] or as Latin -pedicare "to entrap" (from Latin pedica "shackle;" see impeach); and the Spanish and Italian words seem to be related to (perhaps opposites of) Old Provençal empachar "impede." See OED for full discussion. Meaning "to get rid of by killing" is attested from 1520s. [...] As a noun, from 1540s, originally "dismissal;" sense of "a message sent speedily" is first attested 1580s.
1. Why was "to fasten, fix" proposed as a possible etymon? How does it relate?
2. Also, why was "to entrap" proposed as a possible etymon? How does it relate?
Please expose and explain all hidden, missing semantic drifts and links. What is a right way of interpreting the etymology, to understand how the proposed semantic jumps, abstracted and severed from the original literal meaning?
PS: I heeded Etymonline's advice to 'see OED', but neither bridges the proposed semantic jumps.