Should I take special care of my eyes when I inhale Benodil? How long can an open ampoule of Benodil stand?

Good morning, whether during inhalation with Benodil (half ampoule of the drug + half ampoules of saline solution physio. There are no such recommendations in the leaflet. The mask is fitted, but it has holes on the sides and a mist comes out through them when exhaling. Last year, during the inhalation with Atroventem, the child wore swimming goggles, unfortunately now he does not want to wear them. The second question: why does an open ampulke need to be used within 30 minutes. The doctor ordered to use half an amp. in the morning, put it vertically, e.g. in a clean glass and use the rest in the afternoon. I don't know what to think about it. Best regards