It should be capable of operating inside the cockpit, I drove almost the entire length of Valley of the Gods using the beacon from inside my Tacoma, worked like a charm. If this were me, I'd connect the beacon to the drone, then connect the phone to the beacon (my usual method in that order) allow the gps to sync, as soon as it become ready tell it to take off, I watch to ensure it's tracking me, if not I check to see it's on a tracking mode (beacon screen) and wand it some with the blue button if it isn't. I clear the screen on my phone and stick it in my pocket at that time, not touching it for the rest of the flight. At this point I've not used the phone at all except to speed up the gps sync.
This has worked solid for me for a couple years but on the most recent flight I've see some weird behavior just after launching, it's like the drone was tracking something about 50 yards away, moving along with me but offset 50 yards. Landed, powered everything down (Drone/Beacon) restarted and all was good.
When flying the first few min makes all the difference, if it starts out bad like wierd behavior you saw pull it back and start over, cut your losses rather then wasting battery trying to get it working properly. I don't think at that point you can w/o power cycling the drone. That's what happened to me, I couldn't fix the issue using the phone or beacon but restarting it did correct the problem. Shouldn't have to do that and I never have had to do that before but the most recent updates and I suspect the software in the 2+ likely similar, this seems to be a newly created problem with the beacon and phone being used.
One test I'd make is connect the beacon to the drone, then connect the tablet to the beacon, (in that order) allow the gps to sync, when it's ready to launch, disconnect the phone from the beacon taking the phone/tablet out of the equation all together. Wand it around a little to make sure it's locked on and give it a try at tracking you.
It's good to get out in an open area, bring all your batteries and try some different things, much less likely to have an issue with nothing around to interfere. My current drone is new and not allot of flying on it but I'm convinced these get better at tracking you the more you use that function. I know, weird. I won't go as far as to call it learning but my theory is there's a table it's using that gets populated with data it uses on future flights. My last SD2 didn't do so well right at first but got progressively better the more I flew it, after having it for a year it became super rare for it to misbehave at all, almost never. Then the big update and it was like starting over, after a few problematic flights it got much better at tracking me and not loosing it's signal. It fell out of the sky for an unknown reason and skydio gave me another. The new one had some issues like I described above but it's doing allot better, unfortunately it's cold here and I've not flown much with the new drone. It's not the plus version though.