Here's the scene: CJ is locked in the master bathroom and is scheduled
for "the operation" this morning - CJ is a young and energetic cat
while I'm an old and slow arthritic human; practice rounds last night
indicated that when I tried to go into the bathroom, CJ would slip
past and be impossible to catch for a while; the bathroom door opens
onto a hall with two other doors, and a wide open entrance to the
living room with no door.  Problem: how to constrain the cat to an
area where I could corner him - the doors could be closed, but that
left the wide open end.  Solution: partially inflate an air mattress
in a "V" shape across the opening - now all the exits are blocked.

Time came to do this, and it worked well.  Then I took a piece of
plywood to block the door space between and around my legs as I opened
the door, and began to slip inside.  CJ had been screaming and trying
to dig his way under the door most of the night, and had resumed when
I got up this morning.  Now, after all that preparation, he was
quietly resting next to the toilet and cooperated completely in being
picked up and put into the carrier - all that work for nothing.  Of
course, if I had not done it, he would hiding in a closet in a bedroom
or behind the TV and I would never have caught him in time.