Descriptive Problem Summary:
515.1626 (and maybe others) has been sporadically crashing clients when players do various things. I personally am only able to reproduce this issue by using binoculars. However, it often takes several uses to cause a crash; but sometimes it is the first try.

Examples of user reports that are likely related:
https://github.com/cmss13-devs/cmss13/issues/5423
https://github.com/tgstation/tgstation/issues/80910
https://github.com/tgstation/tgstation/issues/80886

Numbered Steps to Reproduce Problem:
https://youtu.be/aY7TMsmvnBI

(Video is before me streamlining the round start process)

1. Start pager and log in (currently doesn't seem to be happy with a guest playing).
2. Clone fork and check out branch Hacked_Out or download code and extract.
3. Compile (e.g. "C:\Program Files (x86)\BYOND\bin\dm.exe" colonialmarines.dme )
4a. Rename folder to colonialmarines and run world in single-user mode (e.g. "C:\Program Files (x86)\BYOND\bin\dreamseeker.exe" D:\cmss13\colonialmarines.dmb ).
4b. Run world in single-user mode console (e.g. "C:\Program Files (x86)\BYOND\bin\dreamseeker.exe" -console D:\cmss13\colonialmarines.dmb ).
4c. Run world in single-user mode trusted (e.g. "C:\Program Files (x86)\BYOND\bin\dreamseeker.exe" -trusted D:\cmss13\colonialmarines.dmb ) You can also attempt using dreamdaemon, but client termination doesn't produce any minidump.
5. Wait for loading to finish (you start readied up, start with CO as your job preference, and round will start immediately as loading finishes)
6. Hold A to move left out of the cryopod
7. Pick up the binoculars on the ground
8. Spam Z (to use the binoculars in your selected hand) and after each attempt try left clicking a turf in a different cardinal direction to face differently.

Code Snippet (if applicable) to Reproduce Problem:
https://github.com/Drulikar/cmss13/tree/Hacked_Out

Expected Results:
Player is able to freely perform actions such as using binoculars to view further ahead without crashing their client.

Actual Results:
Faulting application name: dreamseeker.exe, version: 5.0.515.1626, time stamp: 0x659f57d7
Faulting module name: byondcore.dll, version: 5.0.515.1626, time stamp: 0x659f57b7
Exception code: 0xc0000005
Fault offset: 0x00032ecb
Faulting process id: 0x32a4
Faulting application start time: 0x01da4676448d23c8
Faulting application path: C:\Program Files (x86)\BYOND\bin\dreamseeker.exe
Faulting module path: C:\Program Files (x86)\BYOND\bin\byondcore.dll
Report Id: 47eb917a-746b-4eaa-bfd9-baa2be25ee45
Faulting package full name:
Faulting package-relative application ID:


Fault bucket 1903428235993143860, type 1
Event Name: APPCRASH
Response: Not available
Cab Id: 0

Problem signature:
P1: dreamseeker.exe
P2: 5.0.515.1626
P3: 659f57d7
P4: byondcore.dll
P5: 5.0.515.1626
P6: 659f57b7
P7: c0000005
P8: 00032ecb
P9:
P10:

Does the problem occur:
Every time? Or how often?
Sporadically, sometimes first try, sometimes 5 tries, sometimes 40 tries...
In other games?
At least TG variants of SS13
In other user accounts?
Yes
On other computers?
Yes

When does the problem NOT occur?
Randomly

Did the problem NOT occur in any earlier versions? If so, what was the last version that worked? (Visit http://www.byond.com/download/build to download old versions for testing.)
514.1589 (can test more 515 versions if needed)

Workarounds:
Downgrade Byond version