Hazard Avoidance via Containers

## Description

It's possible to avoid taking damage from a wide variety of hazards by going into a container (e.g. locker or tarp).

## Difference between expected and actual behavior

By containers, I mean things you can physically go into (typically as a human), such as lockers, coffins, and tarps.

Perhaps only part of this is considered unintended, the most notable of which being immunity from queen screeches and boiler gas.

Regarding the following stuff, I am unsure as to whether or not it is a bug, but I think it's good to mention anyway.

One general category of hazard avoidance is explosions. By getting into a thermal tarp, you can avoid taking damage from any standard marine grenade, as well as incendiary OBs (usually). This is similar with a coffin, except that HEFA destroys the coffin (and hurts you) as the coffin is a solid obstacle. This applies if you are activating grenades from within.

You are also immune to fire if you are inside a container.

## Steps to reproduce

### Boiler gas immunity

1. Wait for a boiler to bombard you.
2. Get in a tarp/coffin/container.
3. Wait for gas to subside.
4. Emerge unscathed.

### Queen screech immunity

1. Get in a tarp/container (usually around other people).
2. Wait for queen to screech.
3. Immediately get out of the container (unaffected by queen screech), guns blazing

### Explosion avoidance example

1. Hold HEFAs in both hands.
2. Stand on tarp.
3. Toggle tarp closed (going in it).
4. Activate both grenades.
5. Watch everything around you get sprayed with shrapnel.
6. Emerge unscathed.

## Issue bingo (not required to be all checked)

- [x] Issue could be reproduced at least once
- [ ] Issue happened in a recent (less than 7 days ago) round
- [x] Couldn't find an existing issue about this (https://github.com/cmss13-devs/cmss13/issues)