Modify cardboard box to make really secure?

[LockedInALocker]

Hallo.

     I haven't been here a while - perhaps I am running out of things to say after more than 1,500 posts. But I do have something now to ask of anyone who has thoughts on it - particularly anyone who has had experience with packing people in cardboard boxes, or who has been packed in one themselves.

     I recently received a large parcel in the post, and it was in a large cardboard box about the size of a half-size locker - just right for me to curl up inside! (The item I received was actually a surfboard bag - these being something I quite often use to lock myself in - I occasionally have to get another, as they sometimes start to split apart in one or two places after some time of use, especially if they were a cheaper type. It's not very often that I get two neat, usable containers at the same time.)
     Of course the thought occurred to me about whether it would be possible to modify this box so that I could lock myself and not be able to get out (using my usual trick of a timer controlling a lamp so determining whether or not I can read a padlock). I realized that quite a bit of work would be necessary to make the box suitable secure; and I knew I would not be interested in getting in the box unless it was totally secure, or at least decently difficult to get out of.

     The first thing would need to be making the cardboard strong enough to be unbreakable from inside - and the only way I can think of for doing this is to lay strips of tape all over the outside of the box, covering every square inch. Considering how it can be almost impossible, or even on occasion completely impossible, to break open packages you receive in the mail without cutting implements, it seems to me that sufficient tape should make the box secure.
     In all this, I am assuming that I will not be additionally bound or restrained inside the box. Even if this were my preference (which is isn't), it would not be feasible because my hands must be free to open the lock when the time comes to get out.
     The next issue is to make the box lockable in some way. The box opens on one of the two largest faces by means of large double flaps that open outwards, which is probably less ideal than opening on one of the narrow sides or ends. The only thing I can think of here is to get thin cords of some sort and lay them against the cardboard surfaces in appropriate positions prior to laying down the tape, and use the tape to fix them in place. These would be arranged to form loops in the appropriate places which would come together when I close the box flaps, and I would then use a few padlocks to lock them together. (If it's too dark inside the box to read the lock even when the lamp comes on, I suppose I could cut a tiny slot a fraction of an inch wide in the right place to admit sufficient light.)

     Before I spend quite a bit of time doing all this, I thought I'd ask if anyone here has suggestions. Perhaps the methods I described above won't work well for some reason I haven't anticipated - and it's the only box I have, so I can't afford to mess things up seriously. Does anyone here ever use boxes of this sort? Do they have any useful tips?

  (a) Am I right in believing that the tape would make the box secure?
  (b) What should of tape would be best to use?
  (c) What would be the best way of making the box lockable? The method I described above? Some other way?
  (d) If I were locked in this box, might I get too unbearably hot? (Maybe the tape would make it very insulating.)

     I would appreciate any thoughts on this. Thanks.

Regards, Michael.

[Oblio]

Use the translucent tape with fibers in it.

laminate more cardboard either inside or outside with carpenters glue.