Walking through explosion shockwaves (blast walking)

### Testmerges

N/A

### Round ID

_No response_

### Description of the bug

Sometimes, you can walk into a shockwave tile the same time it travels to your tile, thus bypassing and "dodging" the explosion. This lets you avoid stuns.

https://github.com/user-attachments/assets/56685dad-59b1-4b19-acba-910f612bd8b5

### What's the difference with what should have happened?

The shockwave should apply its effects (stun, damage) to you every single time, as opposed to seemingly being unphased by it.

### How do we reproduce this bug?

1. Throw grenade
2. Get lucky while walking towards it
3. Blast walk through the explosion, thus avoiding injury
...

### Issue Bingo

- [x] Issue could be reproduced at least once
- [x] 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)