Xenos deleted when hijack initially started, not when the dropship takes off

[Mister-moon1]

Testmerges

Not needed

Description of the bug

During the shuttle TGUI rework, the deletion time of xenos was changed from the moment the dropship left the planet to when hijack is initially started.

This has caused the issue of being able to straight up get off the dropship between the starting launch phase and the actual take off of the dropship, allowing you to remain groundside which is unintended, otherswise why is the initial delete in place

What's the difference with what should have happened?

Xenos should be deleted AFTER the dropship takes off for hijack

How do we reproduce this bug?

1. Start hijack
2. Before it takes off, walk off the dropship

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)

[Huffie56]

would be better to have it being done when dropship as taken off to avoid xeno being also able to walk out after hijack got launch...