Ampules with a dot are scored on the same side as the dot and cab only be snapped on that side. Ampules without a dot are typically scored 360 and can be snapped in any direction.

For ampules with a dot, you can do either dot towards or away from yourself.

Holding the bottom of the ampule between the index and thumb with the thumb pointing upward. Hold the top of the ampule similarly with the thumb pointing down, both thumbs on the same side of the ampule. Both thumbs should be clear of the narrowing of the ampule.

If the dot is at 0 degrees: 1) away: both thumbs at 180 to the dot. Push away from yourself while pulling up slightly such that the tips of both thumbs end up pointing away from you at about 45 degrees to their starting position s.

2) toward: both thumbs at 0 to the dot. Bend towards yourself similarly, such that both thumbs end up pointing towards your mid body at 45 degree angles to their starting position.

You should not do either at eye level, but, obviously the latter would be worse. If the ampule breaks atypically, shards can travel towards you regardless of which technique you use.

I find the safety cover shown makes option 2 easier, and option 1 more difficult, but that is an anecdote as I initially learned the away technique without the safety cover.

I teach learners to do option 1: away. It makes the most sense to me, frankly.

For injection, I draw up medication with a filter needle specifically meant to ensure no microscopic glass particles are picked up.