Can I walk away from the gym after I've entered the raid lobby?

I think the game gives you a little leeway if your GPS drifts out of the gym range, but a "network error" kicks you out if you stray too far. I tried this the other day when I was leaving a tier 4 raid no one showed up for--it kicked me out when I got a decent amount away from the gym.

If you give a raid pass you can logout of the game, restart and join the raid again. I have done this a couple times to give potions to my pokemon.

You can stay the lobby, fight the boss, and capture it even if you've strayed a certain distance from the gym (most of the time it locks me onto the gym's location anyway). I managed to completely cross half a park while fighting a Bayleef and capturing it. I'm not sure just how far you can get before it kicks you out though. Same seems to happen for gym battles, I've battled 1 full round while walking 1 block away from it.