I was once locked into two tapes drives

After my first year at University I worked on shift as a computer operator, in Building E machine room.

My job involved
- typing "k e,1" to clear a line from the Master terminal of a System 370 running MFT.
- sitting behind a line printer fanning the greenline paper into the box
when the page ejects were happening faster than the paper feed could handle it
- or performing tape labelling - wiping tapes so they could be re-used.

The tape drives were those big things you see in 70's films
with electrically powered sliding glass windows
that closed automtically so that the tapes could be pulled into loops by a vacuum
- ensuring that they didn't tension the tape too quickly and snap it.

Late one night I was led to a tape drive and demonstrated the
safety aspects of the sliding glass window.

There was a sensor that would detect an object preventing the window from closing.
When the circuit was broken the motor would automatically reverse and the window
would go down. There was a replaceable fuse in the door that, if removed would
cause the window to lock in place.

Well, I was to learn that someone had discovered that if you pushed an arm through the glass
past the elbow and removed the fuse at just the right time, you could effectively trap a person by their arm.I was not the discoverer; I was the person with the arm.

They locked me in and went out to the kermits for a coffee break.

I started getting worried...
- who's going to type "k e,1"
- who's going to fan the paper in that printer
- what if there's a fire and the sprinklers come on and I get electrocuted

I was determined to escape.
I opened another tape drive door, took the fuse from that and replaced the missing
fuse from my door. Freedom!

Trouble is, I can't lie very well.
So I told my captors how I'd escaped.

Next day both arms were trapped.