Friends and the ER

Here's a situation I recently found myself in:

You go to visit a friend, and when you get there, her roommate has gotten Drysol (aluminum chloride hexahydrate 20%....with ethyl alcohol) in her eye. She had been using the Drysol on a staph-infected area. They were washing the eye out with water. You kept washing it out with water, and called poison control. They said do 10 minutes of washing it out, let it rest for half an hour, and if it still hurts after that, go to the ER (the incident occurred at was at midnight). You followed instructions, and she said it still hurt. She said her pain felt like burning, and that pupil was slightly constricted. You suggest that she go to get it checked out. No urgent cares were open that late, so she went to the ER. They checked it out and said some of the irritation was caused by washing the eye with water...it should have been washed with saline. They also gave her some more antibiotics.

Was the ER trip a good idea? Should she have waited until morning?

Why is saline a better choice for eye irrigation?

(edited for clarification)