If you are truly doing tactical training and not just swapping mags you should have some empty casings in the mag (or training rounds) to simulate a ftf. Obviously if you go dry and the slide locks you have to address that with a full drop and reload and sling shot the slide.
In a ftf drill the sequence is tap, rack and fire if appropriate. So, the answer to your question depends on if you are doing tactical reloads going dry, ftf drills or just mag exchanges.
Normally a mag exchange is not done in the heat of battle unlike a tactical reload. The mag exchange is an opportunity to put a fresh mag into the FA from a position of cover prior to re-engaging in the firefight. I would not wast a bullet by training to eject it each time you reload unless you are required to because you are dry.
Also, when doing tactical ftf or reloads, you do not stand there like a dear in the headlights....you seek cover. You will fight the way you train, so train correctly.