(respectfully snipped for focus) Just MHO but I think it clearly is a command, and this is obvious in the very first press conference with the LG cellphone audio;
Delphi Police Conference 02.22.17 FULL | RTV6
Cpt Dave Burstin, beginning at 17m15s in; clip played x 4, twice, beginning at 19 minutes.
This is the original "down the hill" audio; at 17m15s Captain Burstin says it is 'four words .. ah, three words," but this is the clip released originally, without the "Guys" preceeding the command. My own opinion (after listening several times) is that BG clearly says "GO down the hill"--a command, imperative voice.
The emphasis added above is mine; in the audio clip, "go" sounds somewhat minimized, almost slurred. It sounds rather like "G'down the hill" to me. But I clearly hear the word "go" begin the command. Listen for yourself and see what you think.
There are several edited versions of the audio on the web, in which noise has been removed (Tom Webster's "my research" on youtube is the best IMO) and the word "go" is more clearly audible. But this press conference is the first official release of the audio so we know the clip is endorsed by law enforcement.
When LE released the later audio version with the word "Guys" preceeding the command, the "go" is no longer audible, in my opinion. There are probably conspiracy theories about why the audio was released a second time with "guys" added and "go" omitted, though I don't know of any and personally don't see any reason to look for sinister or conspiratorial motives on the part of the police.
Give it a listen; the clip loops 4 times and it is played twice. Listen all the way through and see if you think the actual command was "go down the hill." MOO is that it was.