The train will not forbid the use of medical supplies for awful purposes.

Anything he takes will stay with him and not go back to where he found them at the end of the day so he can steal all the knives and balls he wishes.

Yes if he has the knowledge (and I assume he does) he can make home grown explosives from cleaning supplies, assume a basic level of cleaning chemicals as they get replenished on platforms rather than stored in bulk (though he is welcome to hoard them).

Have fun!