I don't understand the surprise. This is the way a dropped host has always been handled. In the old days, the priest would cover the spot where the host was dropped with a purificator, then come out after Mass and wipe the spot with water.
I haven't seen that done in 40 years. If there are no obvious particles of the host on the floor, then there is no Real Presence there.
I believe you. But I saw it less than a month ago.