Do you mean that you're wondering if it's possible that ether was mixed into the pool water and that that could have knocked them out? I think ether has to be in vapor form so it can be inhaled and enter the blood stream, I doubt it can be absorbed through skin given how volatile it is. And if we're talking about a pool, the sheer amount of ether that would be needed would indeed be impressive. As for holding people without bruising them, sure that's possible, especially if the person doing said holding is also holding an ether soaked handkerchief to the victim's face, they would be knocked out fast and not put up much of a fight.