Learn English – the meaning of “go in all guns blazing” in the following sentence

There are variations of this idiom. I've seen the following:

all guns blazing

guns blazing

guns a-blazing (kind of a Western cowboy variant)

I think it most commonly means "with great energy." From the Cambridge Dictionary:

with guns blazing (also all guns blazing) ​

If you do something, especially argue, with guns blazing, you do it with a lot of force and energy.

(http://dictionary.cambridge.org/us/dictionary/english/with-guns-blazing)

I think the idiom can connote being overly confident or overly stubborn or rushing too much into a situation, as @max_pleaner suggests. Someone who goes in all guns blazing might be seen as careless or inconsiderate or strident.

The connotations can be positive, too. It might be wonderful to witness someone charge into a situation without thinking about it too much.

The example sentence you provide is a little mystifying, because it seems like it's literally suggesting that you don't use real guns to confront an intruder. If this is really the case, then the "guns blazing" idiom is meant to be construed literally. In normal usage, there aren't real guns involved, and the idiom is meant to be construed figuratively. (Strictly speaking, guns can't actually "blaze," unless it's some kind of laser, or maybe a flamethrower. So it'll always be figurative on some level.)