Of course you can. And yes, it is their job. Their job is public saftey. If your neighbor explained what he was about to do and didn’t want any trouble, I’m sure they would have come out, at least until you were in the house. Especially since you said the neighborhood had bike patrol around. And with that fact, why didn’t he call the local dept and advise him so the bike patrol didn’t think you guys were breaking and entering, illegally?
Now, about the opportunity to shoot somebody ~ if we had the Texas law in place, then when that guy came out with a shotgun, if it'd been here, we could have plugged him on the spot couldn't we. No questions asked.
That's why you really do have to be careful who you shoot even if you think the law is on your side.
Sometimes it's simply a case of someone not being polite, and then the guys getting shot are the plumbers who were putting in a new drain while you were on vacation somewhere.
Or, in our hypothetical case here (where we don't have the Texas law, but if we did) anyone who questioned us breaking into my friend's home could be shot ~ wouldn't even have to notice if he had a weapon ~ just note that he was impertinent and nosey ~ then bang.
All these cases where an armed man shoots unarmed people in somebody else's front yard almost all go to trial and he goes to jail.
In some cases it doesn't seem right, but in general it's not good public policy to let folks shoot unarmed people.